Anti-lock brake control method, device, electronic equipment and vehicle of vehicle

Abstract

The present disclosure relates to a kind of vehicle anti-lock braking control method, device, electronic equipment and vehicle, relate to vehicle control technical field.Therein, method includes: in response to triggered anti-lock braking signal, control vehicle enters anti-lock braking state;In anti-lock braking state, motor brake system and hydraulic brake system are braked to vehicle jointly;The braking condition data of vehicle is acquired;Based on braking condition data, only adjust the hydraulic brake parameter when hydraulic brake system is braked to vehicle.This embodiment of the present disclosure can reduce the working noise and mechanical vibration under ABS condition, reduce brake wear, improve the service life of brake system.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle control technology, and in particular to an anti-lock braking control method, device, electronic equipment, and vehicle for a vehicle. Background Technology

[0002] In related technologies, the vehicle's anti-lock braking system (ABS) will stabilize the wheel slip ratio within the optimal operating range by frequently and cyclically adjusting the brake line pressure during emergency braking. This will prevent wheel lock-up from causing skidding and loss of control, while also maximizing braking efficiency and steering control during braking.

[0003] Due to the high-frequency pressure regulation characteristic, ABS generates additional disc-pad friction noise between the brake disc and friction pads during operation. Simultaneously, the frequent operation of the hydraulic pump, solenoid valve body, and other brake system controllers also produces operating noise and mechanical vibration. These factors not only affect ride comfort but also increase brake wear and shorten the lifespan of the braking system. Summary of the Invention

[0004] To address the aforementioned technical problems, this disclosure provides a method, device, electronic equipment, and vehicle for anti-lock braking control of a vehicle, which can reduce operating noise and mechanical vibration under ABS conditions, reduce brake wear, and improve the service life of the braking system.

[0005] In a first aspect, this disclosure provides an anti-lock braking control method for a vehicle, including an electric braking system and a hydraulic braking system; the method includes: In response to the triggered anti-lock braking signal, the vehicle is controlled to enter the anti-lock braking state; in the anti-lock braking state, the electric braking system and the hydraulic braking system work together to brake the vehicle; Obtain vehicle braking condition data; Based on braking condition data, only the hydraulic braking parameters of the hydraulic braking system when braking the vehicle are adjusted.

[0006] In some embodiments of this disclosure, braking condition data includes at least one of the following: road surface adhesion coefficient corresponding to the wheel, vehicle acceleration, vehicle yaw rate, vehicle roll rate, and wheel slip ratio. Based on braking condition data, adjust the hydraulic braking parameters of the hydraulic braking system when braking the vehicle, including: If the road surface adhesion coefficient corresponding to the first wheel is less than a first threshold, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the first wheel; and / or, When the vehicle's angular velocity exceeds a second threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the front wheels and the hydraulic braking parameters of the hydraulic braking system corresponding to the rear wheels; and / or, If the vehicle's yaw rate exceeds the third threshold, or if the tilt rate exceeds the fourth threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the left wheel and the hydraulic braking parameters of the hydraulic braking system corresponding to the right wheel; and / or, Adjust the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel based on the wheel slip ratio of the second wheel, so that the wheel slip ratio of the second wheel matches the target slip ratio range.

[0007] In some embodiments of this disclosure, the maximum value of the target slip ratio range is a first slip ratio, and the minimum value of the target slip ratio range is a second slip ratio; Adjusting the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel based on the wheel slip ratio of the second wheel, so that the wheel slip ratio of the second wheel matches the target slip ratio, including: If the wheel slip ratio of the second wheel is greater than the first slip ratio, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio of the second wheel falls into the target slip ratio range. Alternatively, if the wheel slip ratio corresponding to the second wheel is less than the second slip ratio, increase the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio corresponding to the second wheel falls into the target slip ratio range.

[0008] In some embodiments of this disclosure, controlling the vehicle to enter an anti-lock braking state includes: The motor braking system corresponding to each wheel of the vehicle brakes the vehicle based on the corresponding preset braking parameters.

[0009] In some embodiments of this disclosure, preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a uniform road surface; when the vehicle is traveling on a uniform road surface, the difference between the road surface adhesion coefficients corresponding to each wheel of the vehicle is less than a difference threshold. The preset braking parameters associated with a uniform road surface instruct the motor braking system of each wheel of the vehicle to brake the vehicle with the same motor braking parameters.

[0010] In some embodiments of this disclosure, the preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a split road surface; when the vehicle is traveling on a split road surface, the road surface adhesion coefficient corresponding to the wheel on one side of the vehicle is greater than the road surface adhesion coefficient corresponding to the wheel on the other side of the vehicle. The preset braking parameters associated with the split road surface indicate that the motor braking parameters of the motor braking system of the wheels located on one side of the vehicle are greater than the motor braking parameters of the motor braking system of the wheels located on the other side of the vehicle.

[0011] In some embodiments of this disclosure, preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a connecting road surface; when the vehicle is traveling on a connecting road surface, the road surface adhesion coefficient corresponding to at least one wheel of the vehicle changes from a first adhesion coefficient to a second adhesion coefficient. The preset braking parameters associated with the road surface include at least two preset braking parameters, which are the same number as those corresponding to at least two coefficients of adhesion.

[0012] In some embodiments of this disclosure, the method further includes: Acquire the status information of the motor braking system; the status information includes at least one of the following: available braking torque of the motor, speed controller status, and battery charging power limit. Based on the state information, determine the maximum available braking parameters of the motor braking system; Based on the mapping relationship between braking condition data and braking parameters, the target braking parameters corresponding to the braking condition data are determined. When the maximum available braking parameter is greater than or equal to the target braking parameter, the target braking parameter is determined as the motor braking parameter when the motor braking system brakes the vehicle. Alternatively, if the maximum available braking parameter is less than the target braking parameter, the maximum available braking parameter can be determined as the motor braking parameter.

[0013] In some embodiments of this disclosure, the electric motor braking system includes an electric motor and a battery; the vehicle includes a suspension system; and the mapping relationship between braking condition data and braking parameters is obtained based on the maximum reverse torque capability curve of the electric motor, the maximum continuous charging power of the battery, and the maximum tolerable torque impact of the suspension system under each braking condition parameter.

[0014] In some embodiments of this disclosure, after controlling the vehicle to enter the anti-lock braking state, the method further includes: Update the status information of the motor braking system; Based on the updated status information, determine the updated maximum available braking parameters of the motor braking system; If the updated maximum available braking parameter is less than the motor braking parameter, the updated maximum available braking parameter shall be determined as the updated motor braking parameter. The electric motor braking system is controlled to brake the vehicle based on the updated electric motor braking parameters.

[0015] In some embodiments of this disclosure, after controlling the motor braking system to brake the vehicle based on the updated motor braking parameters, the method further includes: Based on the difference between the updated motor braking parameters and the original motor braking parameters, the hydraulic braking parameters are increased accordingly so that the sum of the increased hydraulic braking parameters and the updated motor braking parameters matches the target braking parameters indicated by the anti-lock braking signal.

[0016] In some embodiments of this disclosure, before controlling the vehicle to enter an anti-lock braking state in response to a triggered anti-lock braking signal, the method further includes: Upon receiving a braking operation, determine the target deceleration and the rate of change of the target deceleration indicated by the braking operation; When the target deceleration is greater than the deceleration threshold and the rate of change of the target deceleration is greater than the rate of change threshold, the anti-lock braking signal is triggered.

[0017] In some embodiments of this disclosure, after controlling the vehicle to enter the anti-lock braking state, the method further includes: If the target deceleration remains less than or equal to the deceleration threshold during the first duration, or if the vehicle speed is less than the speed threshold, the vehicle is controlled to exit the anti-lock braking state, and the motor braking parameters are gradually reduced to 0 during the second duration, while the hydraulic braking parameters are gradually increased to the total braking parameters indicated by the braking operation.

[0018] Secondly, this disclosure also provides an anti-lock braking control device for a vehicle. The vehicle includes an electric braking system and a hydraulic braking system; the anti-lock braking control device includes: The control module is used to control the vehicle to enter the anti-lock braking state in response to the triggered anti-lock braking signal; in the anti-lock braking state, the electric braking system and the hydraulic braking system work together to brake the vehicle; The acquisition module is used to acquire vehicle braking condition data; The adjustment module is used to adjust the hydraulic braking parameters of the hydraulic braking system only when the vehicle is braked, based on braking condition data.

[0019] Thirdly, embodiments of this disclosure provide an electronic device, including: Memory, processor, and computer programs; The computer program is stored in memory and configured to be executed by a processor to implement the anti-lock braking control method as provided in the first aspect.

[0020] Fourthly, embodiments of this disclosure provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the anti-lock braking control method as provided in the first aspect.

[0021] Fifthly, embodiments of this disclosure provide a vehicle, including: Such as electronic equipment provided by a third party; and / or Such as the computer-readable storage medium provided in the fourth aspect.

[0022] The technical solution provided in this disclosure has the following advantages compared with the prior art: The anti-lock braking control method, device, electronic equipment, and vehicle provided in this disclosure reduce the workload of the hydraulic pump and solenoid valve body in the hydraulic braking system by using an electric motor braking system with a fixed torque to participate in anti-lock braking and a hydraulic braking system to dynamically adjust the braking parameters of each wheel according to braking condition data. This reduces the high-frequency operating noise and mechanical vibration generated during the operation of the hydraulic braking system, reduces the high-frequency friction loss between the brake disc and friction pad, extends the service life of the core components of the braking system, and realizes the recovery and utilization of braking energy. Furthermore, the seamless connection of electro-hydraulic braking is achieved through real-time monitoring of the electric motor braking recovery capability and hydraulic compensation. Thus, while ensuring braking safety and vehicle stability, it improves driving comfort and energy recovery efficiency. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A flowchart of an anti-lock braking control method for a vehicle according to some embodiments of the present disclosure is shown; Figure 2 A flowchart illustrating a method for triggering an anti-lock braking signal according to some embodiments of this disclosure is shown; Figure 3 Structural block diagrams of anti-lock braking control devices according to some embodiments of the present disclosure are shown; Figure 4 Structural block diagrams of electronic devices according to some embodiments of the present disclosure are shown. Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0027] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0028] Before describing the embodiments of this disclosure in detail, the technical background involved in this disclosure will be described here so that those skilled in the art can have a clearer understanding of the embodiments of this disclosure.

[0029] In related technologies, the vehicle's anti-lock braking system (ABS) will stabilize the wheel slip ratio within the optimal operating range by frequently and cyclically adjusting the brake line pressure during emergency braking. This will prevent wheel lock-up from causing skidding and loss of control, while also maximizing braking efficiency and steering control during braking.

[0030] In emergency braking scenarios, such as when a driver requests significant braking deceleration within a short period, triggering the ABS anti-lock braking system, the braking force output is entirely handled by traditional hydraulic braking systems, such as Electronic Stability Program (ESP) or Integrated Power Brake (IPB). When a significant braking deceleration is requested, the hydraulic braking system needs to rapidly pressurize, maintain, and depressurize the brake fluid in a cycle. This process can lead to the following problems: 1. Additional disc-pad friction noise is generated between the brake disc and the friction pads, affecting driving comfort; 2. Braking system controllers, such as hydraulic pumps and solenoid valve bodies, generate operating noise and mechanical vibration when working frequently, which will emit high-frequency noise in the range of 2kHz~4kHz; 3. The high-frequency operation of hydraulic braking causes significant wear and tear on the brake discs and friction pads, shortening the service life of the core components of the braking system. 4. Traditional hydraulic braking converts the vehicle's kinetic energy into frictional heat, which is lost and cannot be recovered and utilized.

[0031] In this regard, the present disclosure provides a method, device, electronic equipment, and vehicle for anti-lock braking control of a vehicle, which can reduce operating noise and mechanical vibration under ABS conditions, reduce brake wear, and improve the service life of the braking system. In some embodiments of this disclosure, an anti-lock braking control method for a vehicle is provided. The vehicle includes an electric motor braking system and a hydraulic braking system.

[0032] For example, Figure 1 Flowcharts of anti-lock braking control methods for vehicles according to some embodiments of this disclosure are shown, such as... Figure 1 As shown, the method includes: S102, in response to the triggered anti-lock braking signal, controls the vehicle to enter the anti-lock braking state.

[0033] In the anti-lock braking system (ABS) mode, the electric braking system and the hydraulic braking system work together to brake the vehicle.

[0034] In this embodiment of the disclosure, for example, the braking system controller acquires the driver's braking intention signal at fixed intervals.

[0035] For example, the braking system controller collects the driver's brake pedal signal in real time through the brake pedal displacement sensor, and after filtering, it analyzes the signal to obtain the driver's braking request, which includes the target deceleration value and the rate of change of deceleration.

[0036] The braking system controller compares the target deceleration value with a preset emergency braking deceleration threshold, and also compares the rate of change of deceleration with a preset rate of change threshold. When the target deceleration value is greater than the preset emergency braking deceleration threshold, and the rate of change of deceleration is greater than the preset rate of change threshold, the braking system controller determines that the current state is an emergency braking trigger state, sets the emergency braking flag to the active state, and thus triggers the anti-lock braking signal.

[0037] In some implementations, to avoid false triggering due to signal noise or brief driver error, the braking system controller only confirms the emergency braking state and triggers the anti-lock braking signal after both conditions are met for multiple consecutive data acquisition cycles. This achieves rapid and accurate identification of emergency braking intent, preventing false triggering of the anti-lock braking function.

[0038] Upon triggering of the anti-lock braking signal, the brake system controller puts the vehicle into anti-lock braking mode. In anti-lock braking mode, the brake system controller sends a fixed braking torque request to the electric motor braking system. Based on the current vehicle configuration, the brake system controller queries the calibration parameter set for a preset fixed regenerative braking torque value for the electric motor.

[0039] For example, the fixed regenerative braking torque value of the motor is calibrated and determined during the vehicle development stage based on the maximum reverse torque capability of the electric drive assembly, the maximum charging power limit of the battery system, the maximum reverse torque impact that the suspension system can withstand, as well as vehicle parameters such as vehicle weight and tire rolling radius.

[0040] The calibrated fixed regenerative braking torque value of the motor corresponds to a maximum motor braking deceleration, which can be calibrated differently according to the tolerance of different vehicle architectures.

[0041] The braking system controller uses the fixed regenerative braking torque value of the motor as a constant value and sends a braking torque request of this constant value to the motor braking system.

[0042] Upon receiving the fixed braking torque request, the electric motor braking system participates in braking the vehicle with this fixed electrical value, and this fixed electrical value remains constant throughout the anti-lock braking process. While the electric motor braking system participates in braking with a fixed torque, the braking system controller also sends dynamic adjustment commands to the hydraulic braking system, causing the hydraulic braking system and the electric motor braking system to work together to brake the vehicle.

[0043] Therefore, the electric motor braking system undertakes part of the braking torque output task during anti-lock braking, reducing the total braking torque required by the hydraulic braking system. This lowers the workload of the hydraulic pump and solenoid valve body in the hydraulic braking system, reducing the operating noise and mechanical vibration generated by frequent operation of the hydraulic pump and solenoid valve body. Simultaneously, it reduces high-frequency friction loss between the brake disc and friction pads, extending the service life of the core components of the braking system. Furthermore, the electric motor braking system converts part of the vehicle's kinetic energy into electrical energy during braking and stores it in the power battery, achieving the recovery and utilization of braking energy.

[0044] S104, acquire vehicle braking condition data.

[0045] In this embodiment of the disclosure, during anti-lock braking, the braking system controller acquires vehicle braking condition data. This braking condition data includes the road surface adhesion coefficient, vehicle body dynamics, and wheel slip ratio. The braking system controller acquires the road surface adhesion coefficient through a vehicle state estimation module.

[0046] The vehicle state estimation module utilizes wheel speed sensor signals and six-degree-of-freedom inertial measurement unit signals to estimate the adhesion coefficient of each wheel on the road surface in real time using a Kalman filter algorithm. The module also provides six-degree-of-freedom state information of the vehicle, including longitudinal acceleration, lateral acceleration, vertical acceleration, yaw rate, pitch rate, and roll rate, to characterize the vehicle's dynamic state.

[0047] For example, the braking system controller obtains the actual slip ratio of each wheel through the vehicle state estimation module. This actual slip ratio is calculated in real time by the vehicle state estimation module based on the wheel speed of each wheel and the reference vehicle speed.

[0048] S106, based on braking condition data, only adjusts the hydraulic braking parameters when the hydraulic braking system brakes the vehicle.

[0049] In this embodiment of the present disclosure, the braking system controller adjusts the hydraulic braking parameters of the hydraulic braking system when braking the vehicle based on the acquired braking condition data.

[0050] For example, the hydraulic braking parameters include the hydraulic braking pressure of each wheel. The braking system controller dynamically adjusts the hydraulic braking pressure of each wheel based on the coefficient of adhesion of the road surface where each wheel is located.

[0051] When the coefficient of friction of a certain wheel on the road surface is low, the brake system controller reduces the hydraulic braking pressure of that wheel to prevent wheel lock-up; when the coefficient of friction of a certain wheel on the road surface is high, the brake system controller increases the hydraulic braking pressure of that wheel to improve braking efficiency.

[0052] The braking system controller also dynamically adjusts the hydraulic braking pressure distribution to each wheel based on the vehicle's six degrees of freedom state information. When a negative increase in longitudinal acceleration is detected and exceeds a preset threshold, the braking system controller determines that a longitudinal load transfer has occurred, with the front axle load increasing and the rear axle load decreasing. The braking system controller then increases the hydraulic braking pressure on the front axle wheels and decreases the hydraulic braking pressure on the rear axle wheels to fully utilize the increased traction of the front axle and prevent the rear axle from locking up prematurely due to reduced load.

[0053] When the yaw rate exceeds a preset threshold, the brake system controller determines that the vehicle is prone to fishtailing or skidding. The brake system controller generates a counter-yaw moment by increasing the hydraulic braking pressure on the outer wheels and decreasing the hydraulic braking pressure on the inner wheels to suppress vehicle instability.

[0054] When the detected roll rate exceeds a preset threshold, the brake system controller assists in vehicle attitude control by adjusting the hydraulic braking pressure distribution between the left and right wheels to prevent excessive roll. The brake system controller also compares the actual slip ratio of each wheel with the target slip ratio range.

[0055] When the actual slip ratio of a wheel exceeds the upper limit of the target slip ratio range, the brake system controller determines that the wheel is about to lock up and reduces the slip ratio by decreasing the hydraulic braking pressure of that wheel. When the actual slip ratio of a wheel is less than the lower limit of the target slip ratio range, the brake system controller determines that the wheel is under-braking and increases the braking performance by increasing the hydraulic braking pressure of that wheel. When the actual slip ratio of a wheel is within the target slip ratio range, the brake system controller maintains the current hydraulic braking pressure of that wheel unchanged.

[0056] For example, the braking system controller adjusts the slip ratio using hydraulic braking pressure as the adjustment amount through proportional-integral-derivative closed-loop control.

[0057] Therefore, the hydraulic braking system dynamically adjusts the hydraulic braking pressure of each wheel in a refined and differentiated manner based on changes in the road surface adhesion coefficient, changes in the vehicle's dynamic state, and real-time deviations in the slip ratio of each wheel. This keeps the slip ratio of each wheel within the optimal range. While the electric braking system provides stable basic braking force, it achieves precise control of the wheel slip ratio, preventing wheel lock-up and ensuring braking safety and vehicle stability.

[0058] For a specific example, the braking system controller continuously monitors the regenerative braking capability of the electric motor braking system during the execution of electric motor braking. The braking system controller obtains the current actual available braking torque of each wheel motor from the vehicle controller at fixed intervals, obtains the current upper limit of battery charging power from the battery management system, and obtains the activity status of each motor speed controller from the inverter.

[0059] The braking system controller calculates the difference between the fixed regenerative braking torque value of the motor and the current actual available braking torque of each wheel motor.

[0060] When the difference is greater than zero, the braking system controller determines that the regenerative braking capacity of the motor braking system is insufficient, calculates the braking torque that needs hydraulic compensation, and adds compensation pressure to the current hydraulic braking pressure to increase the hydraulic braking pressure of the corresponding wheel to ensure that the total braking torque does not decrease.

[0061] When the difference is less than or equal to zero, the braking system controller determines that the regenerative braking capacity of the motor braking system is sufficient, and maintains the current hydraulic braking pressure according to the dynamic adjustment logic.

[0062] Once the regenerative braking system's recovery capability is restored, the braking system controller gradually reduces the hydraulic compensation pressure, causing the hydraulic braking pressure to return to its normal value under dynamic adjustment. This achieves seamless connection and smooth switching between electric and hydraulic braking, avoiding torque fluctuations caused by sudden changes in electric braking regenerative capability, and ensuring the smoothness of the braking process and passenger comfort.

[0063] When the vehicle speed drops to a preset low-speed threshold, the braking system controller linearly decreases the motor braking torque from its fixed regenerative braking torque value to zero. Simultaneously, the hydraulic braking pressure linearly increases to compensate for the decrease in motor braking torque, ensuring a smooth transition of total braking torque. When the vehicle speed decreases to a complete stop, the motor braking completely disengages, and the hydraulic braking system independently completes the final braking. This achieves a smooth transition from motor braking to hydraulic braking under low-speed conditions, ensuring stability and safety during low-speed braking.

[0064] In some implementations, the electric motor braking system continuously regenerates kinetic energy while braking the vehicle. During this time, the motor in the system operates in generator mode. Driven by the vehicle's inertia, the motor rotates, converting the vehicle's kinetic energy into electrical energy. An inverter rectifies the AC power generated by the motor into DC power, which is then transmitted to the battery via a high-voltage bus. The battery receives and stores this electrical energy, thus achieving the recovery and utilization of braking energy.

[0065] The electric motor braking system outputs braking torque continuously and stably during anti-lock braking, without high-frequency switching or pulsation of the motor torque. This results in smooth and continuous vehicle deceleration, providing a seamless braking experience for occupants. Simultaneously, the electric motor braking system continuously converts the vehicle's kinetic energy into electrical energy throughout the entire anti-lock braking process, maximizing the recovery and utilization of braking energy and improving the vehicle's range.

[0066] In other embodiments, when braking the vehicle, the electric motor braking system applies braking in a manner similar to an anti-lock braking system (ABS). This ABS-like approach means that the output mode of the electric motor braking system simulates the pressure cycle regulation mode of a hydraulic ABS, periodically adjusting the motor output torque at high frequency during braking.

[0067] In each control cycle, the braking system controller independently determines whether the slip ratio of each wheel is within the target slip ratio range based on the real-time slip ratio value of each wheel. When the actual slip ratio of a wheel exceeds the upper limit of the target slip ratio range, the braking system controller determines that the wheel is about to lock up and immediately reduces the corresponding motor braking torque of the wheel from the current value to a lower value or zero value, so that the wheel speed increases and the slip ratio decreases.

[0068] Once the actual slip ratio of the wheel returns to within the target slip ratio range, the braking system controller restores the corresponding motor braking torque of the wheel from a lower value or zero to the target value or commanded value. The process of reducing and restoring the motor braking torque is repeated at fixed intervals, with the duration of each interval matched to the adjustment frequency of the motor braking system.

[0069] The electric motor braking system independently controls the braking torque of each wheel using the aforementioned high-frequency periodic adjustment method, ensuring that the slip ratio of each wheel remains within the target slip ratio range. The anti-lock braking system adjustment of the electric motor braking system and the pressure adjustment of the hydraulic braking system are performed in parallel.

[0070] The electric motor braking system simulates the pressure cycle regulation mode of a hydraulic anti-lock braking system (ABS) by using high-frequency periodic on / off or up / down adjustments to independently control the electric motor braking torque of each wheel. During the phase where the electric motor braking torque decreases, wheel speed recovers, and the slip ratio falls back to the target range. During the phase where the electric motor braking torque recovers, the wheels regain braking force. This high-frequency periodic adjustment keeps the slip ratio of each wheel consistently near the target slip ratio range, preventing wheel lock-up and maximizing braking efficiency. It achieves rapid and precise control of wheel slip ratio, effectively shortening braking distance while reducing mechanical vibration and operating noise caused by the high-frequency adjustment of the hydraulic braking system, thus improving braking efficiency and ride comfort during ABS braking.

[0071] This embodiment of the invention utilizes a motor braking system that participates in anti-lock braking with a fixed torque, and a hydraulic braking system that dynamically adjusts the braking parameters of each wheel based on braking condition data. This reduces the workload of the hydraulic pump and solenoid valve body in the hydraulic braking system by frequently adjusting them, thereby reducing the high-frequency operating noise and mechanical vibration generated during the operation of the hydraulic braking system, reducing the high-frequency friction loss between the brake disc and the friction pads, extending the service life of the core components of the braking system, and realizing the recovery and utilization of braking energy. Furthermore, by real-time monitoring of the motor braking recovery capability and hydraulic compensation, seamless integration of electro-hydraulic braking is achieved. Thus, while ensuring braking safety and vehicle stability, it improves driving comfort and energy recovery efficiency.

[0072] In some embodiments of this disclosure, braking condition data includes at least one of the following: road surface adhesion coefficient corresponding to the wheel, vehicle acceleration, vehicle yaw rate, vehicle roll rate, and wheel slip ratio. Based on braking condition data, adjust the hydraulic braking parameters of the hydraulic braking system when braking the vehicle, including: If the road surface adhesion coefficient corresponding to the first wheel is less than a first threshold, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the first wheel; and / or, When the vehicle's angular velocity exceeds a second threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the front wheels and the hydraulic braking parameters of the hydraulic braking system corresponding to the rear wheels; and / or, If the vehicle's yaw rate exceeds the third threshold, or if the tilt rate exceeds the fourth threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the left wheel and the hydraulic braking parameters of the hydraulic braking system corresponding to the right wheel; and / or, Adjust the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel based on the wheel slip ratio of the second wheel, so that the wheel slip ratio of the second wheel matches the target slip ratio range.

[0073] In this embodiment of the disclosure, after acquiring braking condition data, the braking system controller executes corresponding hydraulic braking parameter adjustment strategies according to information in different dimensions of the braking condition data.

[0074] For example, the braking condition data includes the road adhesion coefficient corresponding to each wheel. The vehicle state estimation module uses wheel speed sensor signals and six-degree-of-freedom inertial measurement unit signals to estimate the road adhesion coefficient of each wheel in real time through a Kalman filter algorithm, and outputs the adhesion coefficient as part of the braking condition data to the braking system controller.

[0075] The braking system controller compares the road adhesion coefficient corresponding to each wheel with a first threshold. The first threshold is a calibration value used to distinguish between low-adhesion roads and medium-to-high-adhesion roads. For example, the value of the first threshold ranges from 0.3 to 0.5.

[0076] When the road surface adhesion coefficient corresponding to the first wheel is less than the first threshold, the braking system controller determines that the road surface where the first wheel is currently located is a low-adhesion road surface. The braking system controller sends a command to reduce the pressure to the hydraulic brake actuator corresponding to the first wheel in the hydraulic braking system, thereby reducing the hydraulic braking pressure of the first wheel.

[0077] For example, the braking system controller calculates the reduction in hydraulic braking pressure of the first wheel based on the difference between the road surface adhesion coefficient corresponding to the first wheel and a first threshold. This reduction increases as the road surface adhesion coefficient decreases.

[0078] For the other wheels, the braking system controller maintains their respective hydraulic braking pressures constant or adjusts them according to their respective road surface adhesion coefficients. Thus, on low-traction surfaces, the hydraulic braking force of the corresponding wheel is actively reduced, preventing premature wheel lock-up due to insufficient road adhesion, thereby reducing the risk of skidding or loss of control on low-traction surfaces.

[0079] For example, let the road surface adhesion coefficient be μ, then: For high-adhesion road surfaces (μ>0.8), hydraulic braking can withstand greater pressure, and in conjunction with the motor setpoint, it can meet the high deceleration requirements.

[0080] For medium adhesion road surfaces (0.4 < μ ≤ 0.8), hydraulic braking should be appropriately reduced, and motor-driven fixed-value braking should be the primary method.

[0081] For low-adhesion road surfaces (μ≤0.4), hydraulic braking is significantly reduced to prevent wheel lock-up, while motor-driven constant-value braking provides stable deceleration.

[0082] For example, the braking condition data also includes vehicle body acceleration. This vehicle body acceleration is obtained from six-degree-of-freedom state information provided by the vehicle state estimation module, and includes longitudinal acceleration. The braking system controller calculates the vehicle body angular velocity based on the longitudinal acceleration, which is the time rate of change of the longitudinal acceleration and is used to characterize the vehicle's pitch angular velocity.

[0083] The braking system controller compares the vehicle's angular velocity with a second threshold. This second threshold is a calibrated value used to determine whether significant longitudinal load transfer has occurred. During emergency braking, the vehicle body pitches, leading to an increase in front axle load and a decrease in rear axle load. The degree of this load transfer is directly related to the magnitude of the longitudinal deceleration and the vehicle's angular velocity. When the vehicle's angular velocity exceeds the second threshold, the braking system controller determines that a significant longitudinal load transfer has occurred and adjusts the distribution ratio of the hydraulic braking parameters for the front and rear wheels.

[0084] For a specific example, the brake system controller increases the hydraulic braking pressure corresponding to the front wheels and decreases the hydraulic braking pressure corresponding to the rear wheels. The brake system controller calculates the increase in front wheel hydraulic braking pressure and the decrease in rear wheel hydraulic braking pressure based on the difference between the vehicle's angular velocity and a second threshold. This increase and decrease increase as the vehicle's angular velocity increases.

[0085] The braking system controller sends the adjusted front wheel hydraulic braking pressure value to the front wheel hydraulic brake actuator and the adjusted rear wheel hydraulic braking pressure value to the rear wheel hydraulic brake actuator. Thus, during vehicle pitching caused by emergency braking, the front wheels receive greater hydraulic braking force to fully utilize the increased traction of the front axle due to load transfer, while the hydraulic braking force of the rear wheels is appropriately reduced to prevent premature wheel lock-up due to reduced load. This achieves optimal distribution of braking force between the front and rear axles, improving vehicle stability during braking.

[0086] For example, the braking condition data also includes vehicle yaw rate and vehicle roll rate. The vehicle yaw rate and vehicle roll rate are obtained from six-degree-of-freedom state information provided by the vehicle state estimation module. The braking system controller compares the vehicle yaw rate with a third threshold and the vehicle roll rate with a fourth threshold.

[0087] The third threshold is a calibration value used to determine whether the vehicle exhibits a significant yaw tendency, i.e., a fishtailing or sideslip tendency. The fourth threshold is a calibration value used to determine whether the vehicle exhibits a significant roll tendency.

[0088] When the vehicle's yaw rate exceeds the third threshold, the braking system controller determines that the vehicle is prone to fishtailing or skidding. The braking system controller then adjusts the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the left wheel and the hydraulic braking parameters of the hydraulic braking system corresponding to the right wheel.

[0089] For a specific example, the brake system controller increases the hydraulic braking pressure on the outer wheels and decreases the hydraulic braking pressure on the inner wheels, where the outer wheels are those on the side opposite to the vehicle's steering direction, and the inner wheels are those on the side with the same steering direction. The brake system controller calculates the increase in hydraulic braking pressure on the outer wheels and the decrease in hydraulic braking pressure on the inner wheels based on the difference between the vehicle's yaw rate and a third threshold value. These increases and decreases increase as the vehicle's yaw rate increases.

[0090] When the vehicle body roll rate exceeds the fourth threshold, the brake system controller determines that the vehicle has an excessive roll tendency, and the brake system controller also adjusts the distribution ratio of hydraulic braking parameters of the left and right wheels.

[0091] For a specific example, the braking system controller increases the hydraulic braking pressure on the outer wheels and decreases the hydraulic braking pressure on the inner wheels based on the direction and magnitude of the vehicle's roll rate, thereby generating a torque to counteract the roll. The braking system controller then sends the adjusted hydraulic braking pressure values ​​for the left and right wheels to the corresponding hydraulic brake actuators.

[0092] Therefore, when the vehicle exhibits a tendency to fishtail, skid, or excessively tilt, the differential adjustment of the hydraulic braking force of the left and right wheels generates a reverse yaw moment or anti-roll moment. During braking, this simultaneously achieves active correction of the vehicle's lateral attitude, suppresses the tendency to become unstable, and improves the ability to maintain trajectory and the stability of the vehicle body under conditions such as cornering braking or braking on open road surfaces.

[0093] For example, the braking condition data also includes the wheel slip ratio of each wheel. The vehicle state estimation module calculates the actual slip ratio of each wheel in real time based on the wheel speed of each wheel and the reference vehicle speed, and outputs the actual slip ratio as part of the braking condition data to the braking system controller. The braking system controller matches the actual slip ratio of the second wheel with the target slip ratio range.

[0094] For example, the target slip ratio range is a pre-calibrated optimal slip ratio range, with a lower limit of 10% and an upper limit of 20%.

[0095] When the actual slip ratio of the second wheel is greater than the upper limit of the target slip ratio range, the brake system controller determines that the second wheel is about to lock up. The brake system controller sends a command to reduce the pressure to the hydraulic brake actuator corresponding to the second wheel, thereby reducing the hydraulic braking pressure of the second wheel.

[0096] When the actual slip ratio of the second wheel is less than the lower limit of the target slip ratio range, the brake system controller determines that the second wheel is not braking enough. The brake system controller sends a command to the hydraulic brake actuator corresponding to the second wheel to increase the pressure, thereby increasing the hydraulic braking pressure of the second wheel.

[0097] When the actual slip ratio of the second wheel is within the target slip ratio range, the braking system controller maintains the current hydraulic braking pressure of the second wheel unchanged.

[0098] For example, the braking system controller adjusts the hydraulic braking pressure of the second wheel through proportional-integral-derivative (PI-DE) closed-loop control. The input to the P-DE controller is the deviation between the actual slip ratio of the second wheel and the median value of the target slip ratio range, and the output is the adjustment amount of the hydraulic braking pressure of the second wheel. The second wheel can be any one of the vehicle's multiple wheels, and the braking system controller independently executes the aforementioned slip ratio adjustment process for each wheel.

[0099] Therefore, by controlling the actual slip ratio of each wheel within the optimal slip ratio range in a closed loop, each wheel is kept working near the peak of the ground adhesion coefficient, which not only avoids wheel lock-up but also maximizes braking efficiency, thereby effectively shortening the braking distance.

[0100] The aforementioned multiple hydraulic braking parameter adjustment strategies are executed collaboratively by the braking system controller. The braking system controller simultaneously acquires the road adhesion coefficient, vehicle longitudinal acceleration, vehicle yaw rate, vehicle roll rate, and slip ratio of each wheel, and executes the corresponding adjustment logic accordingly.

[0101] When multiple adjustment logics are simultaneously directed to the same wheel, the braking system controller calculates the final hydraulic braking pressure value of that wheel according to a preset priority order.

[0102] For a specific example, closed-loop adjustment based on slip ratio continuously operates as the basic adjustment layer; limiting adjustment based on road adhesion coefficient is superimposed on the basic adjustment layer as a safety protection layer; and front / rear axle and left / right axle distribution adjustment based on vehicle dynamics is superimposed on the basic adjustment layer and / or safety protection layer as an attitude control layer. The braking system controller algebraically adds up the pressure adjustment values ​​output from each layer to obtain the final hydraulic braking pressure value for that wheel.

[0103] Thus, multiple adjustment strategies work together within the same control cycle to achieve refined and multi-dimensional comprehensive control of the hydraulic braking pressure of each wheel, enabling the distribution of braking torque during anti-lock braking to take into account multiple factors such as road adhesion conditions, vehicle longitudinal attitude, and vehicle lateral attitude.

[0104] This embodiment of the invention avoids premature wheel lock-up on low-traction surfaces by adjusting the hydraulic braking pressure of each wheel according to the road surface adhesion coefficient of each wheel; it achieves optimal front-to-rear axle braking force distribution under longitudinal load transfer conditions by adjusting the distribution ratio of front and rear wheel hydraulic braking pressure according to the vehicle body angular velocity; it achieves rapid generation of reverse yaw moment and anti-roll moment under lateral instability by adjusting the distribution ratio of left and right wheel hydraulic braking pressure according to the vehicle body yaw and roll angular velocities; and it maximizes braking efficiency by maintaining the slip ratio of each wheel within the optimal range through closed-loop adjustment of the slip ratio of each wheel. The coordinated execution of the above multiple adjustment strategies solves the technical problem that a single adjustment dimension cannot take into account multiple dynamic factors such as road surface adhesion differences, vehicle pitch, vehicle yaw, and roll during anti-lock braking. Thus, under the premise that the electric motor braking system provides stable basic braking force, it achieves precise and comprehensive control of the braking pressure of each wheel by the hydraulic braking system, further improving braking efficiency, vehicle stability, and driving safety during anti-lock braking.

[0105] In some embodiments of this disclosure, controlling the vehicle to enter an anti-lock braking state includes: The motor braking system corresponding to each wheel of the vehicle brakes the vehicle based on the corresponding preset braking parameters.

[0106] In this embodiment of the disclosure, after the anti-lock braking signal is triggered, the braking system controller controls the vehicle to enter the anti-lock braking state.

[0107] For example, multiple wheels of the vehicle are each equipped with an independent electric motor brake, and each electric motor brake can independently receive braking torque commands and independently output braking torque. After entering the anti-lock braking state, the braking system controller determines the preset braking parameters of the electric motor brake system corresponding to each wheel. The preset braking parameters corresponding to each wheel are independently stored in the non-volatile memory of the braking system controller, and each preset braking parameter is independently calibrated according to the characteristics of the motor corresponding to that wheel during the vehicle development stage.

[0108] For example, in a vehicle with a four-motor, four-wheel-drive architecture, each wheel is equipped with an independent drive motor that acts as a generator during braking and provides reverse braking torque. The left front wheel motor, right front wheel motor, left rear wheel motor, and right rear wheel motor each have independent power ratings, independent torque output capabilities, and independent cooling characteristics.

[0109] The braking system controller reads the preset braking torque values ​​corresponding to the left front wheel motor, the right front wheel motor, the left rear wheel motor, and the right rear wheel motor from the calibration parameter set. These four preset braking torque values ​​can be the same or different depending on the specifications of the different wheel motors.

[0110] For example, in a vehicle with a dual-motor four-wheel drive architecture, the front axle motor drives both the left and right front wheels simultaneously, and the rear axle motor drives both the left and right rear wheels simultaneously. The braking system controller reads the preset braking torque values ​​corresponding to the front axle motor and the rear axle motor from the calibration parameter set, and uses the preset braking torque value of the front axle motor as a preset braking parameter shared by the left and right front wheels, and the preset braking torque value of the rear axle motor as a preset braking parameter shared by the left and right rear wheels.

[0111] The braking system controller sends the preset braking parameters for each wheel to the corresponding motor brake.

[0112] For example, the braking system controller sends a preset braking torque command for the left front wheel to the left front wheel motor controller, a preset braking torque command for the right front wheel to the right front wheel motor controller, a preset braking torque command for the left rear wheel to the left rear wheel motor controller, and a preset braking torque command for the right rear wheel to the right rear wheel motor controller via a control area network bus. Each motor controller responds to the received braking torque command by controlling its corresponding motor to output the corresponding reverse braking torque. Throughout the anti-lock braking process, the motor brakes of each wheel continuously output braking torque according to their respective preset braking parameters until the anti-lock braking state is exited or the braking parameters of each wheel motor are updated according to the adaptive adjustment logic in the aforementioned embodiments. The motor braking systems of each wheel operate independently; a change in the braking parameters of one wheel motor does not affect the braking parameter settings of other wheel motors.

[0113] This embodiment of the invention controls the motor braking systems of each wheel of a vehicle to brake the vehicle based on corresponding preset braking parameters. This allows each wheel's motor braking system to independently receive and execute braking torque commands, solving the technical problem in multi-wheel control architectures where the same braking parameters for each wheel's motors in anti-lock braking systems cannot adapt to the independent braking hardware characteristics and operating conditions of each wheel. The preset braking parameters for each wheel are independently calibrated according to the specifications, heat dissipation conditions, and power rating of their respective motors, ensuring that the braking output of each wheel's motor matches its physical capabilities. In the four-motor architecture, each wheel can achieve truly independent motor braking control, with the braking parameters of each wheel's motors not affecting each other. This achieves independent setting and control of the braking torque for each wheel's motor, and each wheel's motor braking system outputs braking force within its own capability boundaries. The multi-motor independent control capability of the motor braking system and the differentiated characteristics of different wheel motors are fully utilized, further improving the accuracy of motor braking participation and the flexibility of braking force distribution among wheels during anti-lock braking.

[0114] In this embodiment of the disclosure, the preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a uniform road surface; when the vehicle is traveling on a uniform road surface, the difference between the road surface adhesion coefficients corresponding to each wheel of the vehicle is less than the difference threshold. The preset braking parameters associated with a uniform road surface instruct the motor braking system of each wheel of the vehicle to brake the vehicle with the same motor braking parameters.

[0115] In this embodiment of the disclosure, before determining the preset braking parameters of the motor braking system corresponding to each wheel, the braking system controller first obtains the road surface state of the road surface on which the vehicle is currently traveling.

[0116] For example, the braking system controller obtains the road surface adhesion coefficient corresponding to each wheel through the vehicle state estimation module and calculates the difference between the road surface adhesion coefficients of each wheel. When the difference between the road surface adhesion coefficients corresponding to each wheel is less than a preset difference threshold, the braking system controller determines that the vehicle is currently traveling on a uniform road surface.

[0117] For example, the difference threshold can be set to 0.1, meaning that when the difference in the road surface adhesion coefficient between each wheel is within 0.1, the road surface is considered a uniform road surface. Uniform road surfaces include road surface types with a uniformly distributed adhesion coefficient, such as dry asphalt road surfaces, wet asphalt road surfaces, and snow-covered road surfaces.

[0118] After determining that the vehicle is traveling on a uniform road surface, the braking system controller queries the calibration parameter set for preset braking parameters associated with the uniform road surface. These preset braking parameters instruct the electric braking systems of each wheel to apply the same braking parameters. For vehicles with a four-motor four-wheel drive architecture, the braking system controller reads a unified preset braking torque value and uses this value as the common preset braking parameter for the left front wheel motor, right front wheel motor, left rear wheel motor, and right rear wheel motor. For vehicles with a two-motor four-wheel drive architecture, the braking system controller sets the preset braking torque values ​​for the front axle motor and the rear axle motor to the same value.

[0119] The braking system controller sends the same preset braking torque value to the corresponding motor brakes of each wheel. Each wheel's motor braking system responds to this command, participating in anti-lock braking with the same braking torque output value. On a uniform road surface, since the coefficient of friction of each wheel is basically the same, the adhesion capability of each wheel is the same. Using the same motor braking torque for each wheel will not cause any wheel to lock up before the others due to excessive motor braking force. The hydraulic braking systems of each wheel independently adjust their hydraulic braking pressure according to the adjustment logic based on slip ratio and vehicle dynamics described in the preceding embodiments, while the motor braking system provides a unified basic braking force platform.

[0120] When the braking system controller detects in a subsequent control cycle that the difference between the road surface adhesion coefficients of each wheel increases to a value greater than or equal to a difference threshold, the braking system controller determines that the road surface state has switched from a uniform road surface to a non-uniform road surface. At this time, according to the logic in the aforementioned embodiments, the braking system controller determines a separate preset braking parameter for each wheel, and the motor braking systems of each wheel no longer brake with the same parameters. For example, when the vehicle travels from a uniform road surface to a split road surface, the difference between the road surface adhesion coefficients of the left and right wheels increases and exceeds the difference threshold. The motor braking parameters corresponding to the left and right wheels are set independently, and the two are no longer the same.

[0121] This embodiment of the disclosure solves the technical problem of unnecessary increase in control complexity caused by setting different motor braking parameters for each wheel when the adhesion of each wheel is consistent under uniform road conditions. By associating preset braking parameters with road surface conditions, it instructs the motor braking system of each wheel to brake with the same motor braking parameters under uniform road surface conditions. Under uniform road surface conditions, the road adhesion conditions of each wheel are the same, and using the same motor braking torque for each wheel will not cause braking imbalance among the wheels, nor will it cause additional yaw moment or vehicle instability. Setting unified motor braking parameters reduces the computational and communication burden of the multi-motor control system, improving the system's control efficiency under uniform road surface conditions. When the road surface condition switches from uniform to non-uniform, the braking system controller automatically switches to the mode of independent motor braking parameters for each wheel. Therefore, the setting mode of motor braking parameters adaptively matches the road surface condition, optimizing the resource allocation and response efficiency of the multi-motor control system while ensuring braking safety and stability.

[0122] In some embodiments of this disclosure, the preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a split road surface; when the vehicle is traveling on a split road surface, the road surface adhesion coefficient corresponding to the wheel on one side of the vehicle is greater than the road surface adhesion coefficient corresponding to the wheel on the other side of the vehicle. The preset braking parameters associated with the split road surface indicate that the motor braking parameters of the motor braking system of the wheels located on one side of the vehicle are greater than the motor braking parameters of the motor braking system of the wheels located on the other side of the vehicle.

[0123] In this embodiment of the present disclosure, before determining the preset braking parameters of the motor braking system corresponding to each wheel, the braking system controller first obtains the road surface state of the current driving surface. The braking system controller obtains the road surface adhesion coefficient corresponding to each wheel through the vehicle state estimation module, and calculates the difference between the road surface adhesion coefficients corresponding to the wheels located on the left side of the vehicle and the wheels located on the right side of the vehicle.

[0124] When the difference between the road surface adhesion coefficients corresponding to the left and right wheels is greater than or equal to a preset difference threshold, the braking system controller determines that the vehicle is currently traveling on a split road surface. The difference threshold can be set to 0.1.

[0125] Split-road surfaces are a typical type of non-uniform road surface, characterized by the left and right wheels of a vehicle being on different road surfaces with significantly different adhesion conditions. For example, the left wheel may be on a dry asphalt road surface while the right wheel is on an icy or snowy road surface, or the left wheel may be on a wet and slippery epoxy floor while the right wheel is on a dry cement road surface.

[0126] After determining that the vehicle is traveling on a split road surface, the braking system controller further identifies the side with a high coefficient of friction and the side with a low coefficient of friction. When the coefficient of friction for the left wheel is greater than that for the right wheel, the braking system controller determines the left side of the vehicle to be the high-friction side and the right side to be the low-friction side. Conversely, when the coefficient of friction for the right wheel is greater than that for the left wheel, the braking system controller determines the right side of the vehicle to be the high-friction side and the left side to be the low-friction side.

[0127] The braking system controller queries the calibration parameter set for preset braking parameters associated with the split-road surface. The preset braking parameters associated with the split-road surface indicate that the motor braking parameters of the electric braking system for the wheels located on one side of the vehicle are greater than the motor braking parameters of the electric braking system for the wheels located on the other side of the vehicle.

[0128] For example, the braking system controller sets the preset braking parameters of the motor braking system corresponding to the high-adhesion side wheels as the first preset braking torque value, and sets the preset braking parameters of the motor braking system corresponding to the low-adhesion side wheels as the second preset braking torque value. The first preset braking torque value is greater than the second preset braking torque value. The specific values ​​of the first and second preset braking torque values ​​are determined separately based on the road adhesion coefficient values ​​of the high-adhesion and low-adhesion sides. The higher the road adhesion coefficient on the high-adhesion side, the greater the first preset braking torque value. The lower the road adhesion coefficient on the low-adhesion side, the smaller the second preset braking torque value.

[0129] For vehicles with a four-motor four-wheel drive architecture, when the left side of the vehicle is the high-traction side and the right side is the low-traction side, the braking system controller sets the preset braking parameters of the left front wheel motor and the left rear wheel motor to the first preset braking torque value, and sets the preset braking parameters of the right front wheel motor and the right rear wheel motor to the second preset braking torque value. When the right side of the vehicle is the high-traction side and the left side is the low-traction side, the braking system controller sets the preset braking parameters of the right front wheel motor and the right rear wheel motor to the first preset braking torque value, and sets the preset braking parameters of the left front wheel motor and the left rear wheel motor to the second preset braking torque value.

[0130] The braking system controller sends the motor braking parameters corresponding to the high-adhesion-side wheels to the corresponding motor brakes on the high-adhesion-side wheels, and the motor braking parameters corresponding to the low-adhesion-side wheels to the corresponding motor brakes on the low-adhesion-side wheels. Each wheel's motor braking system responds to the received commands and outputs braking torque according to its corresponding preset braking parameters. The motor braking system of the high-adhesion-side wheels outputs a larger braking torque, while the motor braking system of the low-adhesion-side wheels outputs a smaller braking torque. Throughout the anti-lock braking process, the motor braking parameters of the left and right wheels maintain the aforementioned differentiated set values ​​until the anti-lock braking state is disengaged or the road surface conditions change.

[0131] When the braking system controller detects in a subsequent control cycle that the difference between the road surface adhesion coefficients of the left and right wheels has decreased to less than a difference threshold, the braking system controller determines that the road surface state has switched from a split road surface to a uniform road surface. At this time, according to the logic in the aforementioned embodiments, the braking system controller switches the preset braking parameters of each wheel motor to the same preset braking parameter values ​​associated with a uniform road surface.

[0132] This embodiment of the invention configures the preset braking parameters of the split-surface road surface to indicate that the motor braking parameters of the high-adhesion side wheels are greater than those of the low-adhesion side wheels. This allows the motor braking system to output differentiated braking torque based on the difference in adhesion capabilities between the left and right sides on split-surface roads. This solves the technical problem that in conditions such as split-surface roads where the left and right adhesion coefficients differ significantly, using the same motor braking parameters for all wheels may lead to the low-adhesion side wheels locking up due to excessive motor braking force, while the high-adhesion side wheels' motor braking force is not fully utilized. On the high-adhesion side, the larger motor braking torque fully utilizes the higher road surface adhesion on that side, providing a greater contribution to braking deceleration. On the low-adhesion side, the smaller motor braking torque limits the motor braking force of the wheels on that side to within the allowable range of road surface adhesion capability, avoiding wheel lock-up caused by the motor braking force exceeding the adhesion limit. The difference in motor braking torque between the left and right sides itself generates a reverse yaw moment opposite to the vehicle's yaw direction. This reverse yaw moment begins to act simultaneously with the initiation of motor braking, actively suppressing the yaw tendency of the vehicle caused by uneven braking force between the left and right sides. Thus, the electric motor braking system simultaneously maximizes the braking efficiency on the high-adhesion side, provides anti-lock braking protection on the low-adhesion side, and actively enhances lateral stability on split-road surfaces, thereby improving the braking safety and vehicle stability of the anti-lock braking system under this extreme condition.

[0133] In some embodiments of this disclosure, preset braking parameters are associated with the road surface condition of the road surface on which the vehicle travels; the road surface condition includes a connecting road surface; when the vehicle is traveling on a connecting road surface, the road surface adhesion coefficient corresponding to at least one wheel of the vehicle changes from a first adhesion coefficient to a second adhesion coefficient. The preset braking parameters associated with the road surface include at least two preset braking parameters, which are the same number as those corresponding to at least two coefficients of adhesion.

[0134] In this embodiment of the disclosure, before determining the preset braking parameters of the motor braking system corresponding to each wheel, the braking system controller first obtains the road surface state of the current driving surface. The braking system controller monitors the road surface adhesion coefficient corresponding to each wheel in real time through the vehicle state estimation module, and compares the road surface adhesion coefficient at the current moment with the road surface adhesion coefficient at the previous moment to calculate the time change rate of the road surface adhesion coefficient.

[0135] When the road surface adhesion coefficient corresponding to a certain wheel changes from a first adhesion coefficient to a second adhesion coefficient within a preset time window, and the difference between the first adhesion coefficient and the second adhesion coefficient is greater than a preset change threshold, the braking system controller determines that the vehicle is currently traveling on the contact road surface. The change threshold can be set to 0.3.

[0136] A transitional road surface is a type of road where the coefficient of adhesion changes abruptly along the direction of vehicle travel. For example, a vehicle may travel from a dry asphalt surface to an icy or snow-covered surface, or from an epoxy floor to a dry concrete surface. On a transitional road surface, different wheels of a vehicle may be in areas with different coefficients of adhesion at the same time, or the same wheel may experience abrupt changes in the coefficient of adhesion at different times.

[0137] After determining that the vehicle is traveling on the connecting road surface, the braking system controller further identifies the target wheel where the road surface adhesion coefficient abruptly changes, as well as the adhesion coefficient values ​​before and after the change. The braking system controller records the first adhesion coefficient of the target wheel before the change and the second adhesion coefficient after the change. The first adhesion coefficient corresponds to the road surface adhesion level before the vehicle enters the connecting road surface, and the second adhesion coefficient corresponds to the road surface adhesion level after the vehicle enters the connecting road surface.

[0138] The braking system controller queries the calibration parameter set for preset braking parameters associated with the road surface. The preset braking parameters associated with the road surface include at least two preset braking parameters, the same number as those corresponding to at least two adhesion coefficients.

[0139] For a specific example, the braking system controller determines a first preset braking torque value associated with the first adhesion coefficient and a second preset braking torque value associated with the second adhesion coefficient based on the first and second adhesion coefficients before and after the sudden change in the target wheel's adhesion coefficient. The first and second preset braking torque values ​​are stored under different entries in the calibration parameter set, and each is calibrated independently. The value of the first preset braking torque value matches the first adhesion coefficient, taking a larger value when the first adhesion coefficient is high and a smaller value when the first adhesion coefficient is low. Similarly, the value of the second preset braking torque value matches the second adhesion coefficient, taking a larger value when the second adhesion coefficient is high and a smaller value when the second adhesion coefficient is low.

[0140] During the transition from a first coefficient of friction to a second coefficient of friction for the target wheel, the braking system controller switches the preset braking parameters of the corresponding motor braking system from a first preset braking torque value to a second preset braking torque value. The braking system controller immediately initiates the preset braking parameter switching operation when it detects that the target wheel's coefficient of friction begins to change from the first to the second coefficient of friction.

[0141] The switching process is executed smoothly within a second time period, which can be set to 100 milliseconds to 300 milliseconds, for example. The braking system controller gradually adjusts the preset braking parameters of the target wheel from a first preset braking torque value to a second preset braking torque value according to a transition curve, so that the motor braking torque of the wheel is synchronously adapted as the road surface adhesion coefficient changes.

[0142] For vehicles with a four-motor, four-wheel-drive architecture, when the road surface affects only a single wheel, only the preset braking parameters of the motor braking system corresponding to that wheel undergo the aforementioned switching operation, while the preset braking parameters of the other three wheels remain unchanged. When the road surface simultaneously affects multiple wheels, for example, when a vehicle travels from a dry asphalt road to an icy or snow-covered road surface and the left front and left rear wheels experience sudden changes in the coefficient of friction, the braking system controller independently executes the preset braking parameter switching operation for each affected wheel. The switching start point and duration for each wheel are independently determined based on the actual moment when that wheel detects the sudden change in the road surface coefficient of friction.

[0143] When the braking system controller detects in a subsequent control cycle that the road surface adhesion coefficient of the target wheel is stable at the second adhesion coefficient and no longer changes further, the braking system controller completes the switching of the preset braking parameters and maintains the preset braking parameters of the target wheel at the second preset braking torque value until the vehicle leaves the docking road surface or the road surface condition changes again.

[0144] This embodiment of the invention configures the preset braking parameters associated with the road surface to include at least two preset braking parameters corresponding to at least two adhesion coefficients. During the change of the road surface adhesion coefficient from a first adhesion coefficient to a second adhesion coefficient, the preset braking parameters are controlled to switch from the first preset braking parameter to the second preset braking parameter. This allows the preset braking parameters of the motor braking system to adjust synchronously with the abrupt changes in the road surface adhesion coefficient on the road surface, solving the technical problem that a single fixed preset braking parameter cannot adapt to the significantly different adhesion conditions before and after the abrupt change in road surface adhesion coefficient, such as on the road surface. When the wheel moves from a high-adhesion road surface to a low-adhesion road surface, the preset braking parameters decrease synchronously, preventing the wheel from locking up on the low-adhesion section due to excessively high motor power. When the wheel moves from a low-adhesion road surface to a high-adhesion road surface, the preset braking parameters increase synchronously, enabling the motor braking system to output greater braking torque in a timely manner on the high-adhesion section to fully utilize the road surface adhesion. The switching of the preset braking parameters is synchronized with the change in the road surface adhesion coefficient, and the switching process is smoothly executed within the second time period, without abrupt changes in braking torque. Therefore, the motor braking system achieves real-time matching between preset braking parameters and current adhesion conditions under the condition of sudden changes in the adhesion coefficient when docking with the road surface. The motor braking output is always adapted to the current road surface adhesion capability, which improves the adaptive capability and braking safety of the anti-lock braking system under the condition of sudden changes in the road surface adhesion coefficient.

[0145] In some embodiments of this disclosure, the maximum value of the target slip ratio range is a first slip ratio, and the minimum value of the target slip ratio range is a second slip ratio; Adjusting the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel based on the wheel slip ratio of the second wheel, so that the wheel slip ratio of the second wheel matches the target slip ratio, including: If the wheel slip ratio of the second wheel is greater than the first slip ratio, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio of the second wheel falls into the target slip ratio range. Alternatively, if the wheel slip ratio corresponding to the second wheel is less than the second slip ratio, increase the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio corresponding to the second wheel falls into the target slip ratio range.

[0146] In this embodiment of the disclosure, for example, the target slip ratio range is a pre-calibrated optimal slip ratio range, with the maximum value of the target slip ratio range being a first slip ratio and the minimum value being a second slip ratio.

[0147] For example, the first slip ratio ranges from 15% to 30%, such as 20%. For example, the second slip ratio ranges from 5% to 14%, such as 10%.

[0148] The first and second slip ratios together define the optimal operating range of wheel slip ratio. When the wheel slip ratio is within this target slip ratio range, the coefficient of adhesion between the wheel and the road surface is close to the peak coefficient of adhesion, which can provide maximum braking force and maintain sufficient lateral force to ensure the vehicle's steering control and lateral stability.

[0149] After obtaining the actual slip ratio of the second wheel from the vehicle state estimation module, the braking system controller compares the actual slip ratio of the second wheel with the first slip ratio and the second slip ratio respectively. The second wheel can be any one of the multiple wheels of the vehicle, and the braking system controller independently performs the slip ratio comparison and adjustment process for each wheel.

[0150] When the slip ratio of the second wheel is greater than that of the first wheel, the braking system controller determines that the second wheel is about to lock up. In this state, the wheel speed is significantly lower than the reference vehicle speed, the slip component between the wheel and the road surface is too large, the lateral adhesion of the wheel decreases sharply, and the vehicle is at risk of losing steering ability and lateral stability.

[0151] The braking system controller sends a command to the hydraulic brake actuator corresponding to the second wheel to reduce the hydraulic braking pressure, thereby reducing the clamping force of the brake caliper of the second wheel, thus increasing the wheel speed of the second wheel and reducing the slip ratio.

[0152] The braking system controller continuously executes the above comparison and adjustment process in a fixed control cycle. In each control cycle, the braking system controller calculates the pressure reduction of the current cycle according to the proportional-integral-derivative control law based on the difference between the actual slip ratio of the second wheel and the first slip ratio.

[0153] The braking system controller reduces the hydraulic braking pressure of the second wheel cycle by cycle, and re-acquires the actual slip ratio of the second wheel in each cycle and compares it with the first slip ratio.

[0154] When the actual slip ratio of the second wheel decreases to less than or equal to the first slip ratio, the braking system controller stops reducing the hydraulic braking pressure of the second wheel.

[0155] If the actual slip ratio of the second wheel is still greater than the second slip ratio, that is, the actual slip ratio has fallen back into the target slip ratio range, the braking system controller maintains the current hydraulic braking pressure and continues to maintain braking at the current pressure.

[0156] If the actual slip ratio of the second wheel decreases directly from greater than the first slip ratio to less than the second slip ratio during the adjustment process, that is, the slip ratio spans the entire target slip ratio range in a single adjustment, the brake system controller will switch to the adjustment mode of increasing hydraulic braking pressure after detecting that the slip ratio is less than the second slip ratio.

[0157] Therefore, by comparing and adjusting cycle by cycle, the slip ratio of the second wheel is pulled back from the lock-up risk area to the target slip ratio range, thus eliminating the lock-up risk without introducing excessive pressure oscillations.

[0158] When the wheel slip ratio of the second wheel is less than the second slip ratio, the braking system controller determines that the second wheel is under-braking. In this state, the wheel speed is too close to the reference vehicle speed, the slip component between the wheel and the road surface is too small, the braking friction is not fully utilized, the vehicle's braking deceleration does not reach the maximum value under the current road surface adhesion conditions, and there is a risk of increased braking distance.

[0159] The braking system controller sends a command to the hydraulic brake actuator corresponding to the second wheel to increase the hydraulic braking pressure, thereby increasing the clamping force of the brake caliper of the second wheel, which in turn reduces the wheel speed of the second wheel and increases the slip ratio.

[0160] The braking system controller continuously executes the above comparison and adjustment process in a fixed control cycle. In each control cycle, the braking system controller calculates the pressure increase of the current cycle according to the proportional-integral-derivative control law based on the difference between the actual slip ratio of the second wheel and the second slip ratio.

[0161] The braking system controller increases the hydraulic braking pressure of the second wheel cycle by cycle, and reacquires the actual slip ratio of the second wheel in each cycle and compares it with the second slip ratio.

[0162] When the actual slip ratio of the second wheel increases to be greater than or equal to the second slip ratio, the braking system controller stops increasing the hydraulic braking pressure of the second wheel.

[0163] If the actual slip ratio of the second wheel is still less than the first slip ratio, that is, the actual slip ratio has returned to the target slip ratio range, the braking system controller maintains the current hydraulic braking pressure and continues to maintain braking at the current pressure.

[0164] If the actual slip ratio of the second wheel increases directly from less than the second slip ratio to greater than the first slip ratio during the adjustment process, the brake system controller will switch to the adjustment mode of reducing hydraulic braking pressure after detecting that the slip ratio is greater than the first slip ratio.

[0165] Therefore, by comparing and adjusting cycle by cycle, the slip ratio of the second wheel is increased from the insufficient braking area to the target slip ratio range, so as to fully utilize the ground braking force without introducing the risk of wheel lock-up.

[0166] The brake system controller independently performs the slip ratio adjustment process for each wheel. For each of the left front wheel, right front wheel, left rear wheel, and right rear wheel, the brake system controller obtains the actual slip ratio of that wheel, compares it with the first slip ratio and the second slip ratio, and sends an independent pressure adjustment command to the hydraulic brake actuator corresponding to that wheel.

[0167] When one wheel has an excessively high slip ratio while another wheel has an excessively low slip ratio, the braking system controller simultaneously applies pressure adjustments in opposite directions to both wheels, causing the slip ratio of each wheel to converge towards the target slip ratio range. This achieves independent and parallel adjustment of the slip ratio of multiple wheels.

[0168] For example, the above-described slip ratio adjustment process is executed in conjunction with hydraulic brake pressure adjustment based on the road surface adhesion coefficient. The brake system controller acquires the actual slip ratio of the second wheel, as well as the corresponding road surface adhesion coefficient.

[0169] When the road surface adhesion coefficient corresponding to the second wheel is low, the second wheel may enter a locked state with a slip ratio greater than the first slip ratio under a small hydraulic braking pressure. At this time, the slip ratio adjustment process reduces the hydraulic braking pressure of the second wheel to a low level.

[0170] When the road surface adhesion coefficient corresponding to the second wheel is high, the second wheel can withstand greater hydraulic braking pressure without locking up. At this time, the slip ratio adjustment process allows the hydraulic braking pressure of the second wheel to be adjusted within a higher range.

[0171] Thus, the combined effect of slip ratio adjustment and road surface adhesion coefficient adjustment enables each wheel to be controlled within the target slip ratio range on road surfaces with different adhesion conditions, thereby maximizing braking performance.

[0172] This embodiment of the invention defines a target slip ratio range as a numerical range defined by a first slip ratio and a second slip ratio. When the actual slip ratio exceeds this range, the hydraulic braking pressure is gradually adjusted periodically towards the inner edge of the range until the actual slip ratio falls back into the target slip ratio range. This achieves precise closed-loop control of the slip ratio for each wheel. When a wheel tends to lock up, the method actively reduces the hydraulic braking pressure to bring the slip ratio back to the optimal range; when wheel braking is insufficient, the method actively increases the hydraulic braking pressure to raise the slip ratio to the optimal range. Thus, the slip ratio of each wheel is always maintained within the target slip ratio range close to the peak adhesion coefficient. This avoids the risks of sideslip and loss of control caused by wheel lockup, while achieving the maximum braking deceleration under current road conditions. This effectively shortens the braking distance during anti-lock braking while maintaining the vehicle's steering control and lateral stability.

[0173] In some embodiments of this disclosure, the method further includes: Acquire the status information of the motor braking system; the status information includes at least one of the following: available braking torque of the motor, speed controller status, and battery charging power limit. Based on the state information, determine the maximum available braking parameters of the motor braking system; Based on the mapping relationship between braking condition data and braking parameters, the target braking parameters corresponding to the braking condition data are determined. When the maximum available braking parameter is greater than or equal to the target braking parameter, the target braking parameter is determined as the motor braking parameter when the motor braking system brakes the vehicle. Alternatively, if the maximum available braking parameter is less than the target braking parameter, the maximum available braking parameter can be determined as the motor braking parameter.

[0174] In this embodiment of the disclosure, after the anti-lock braking signal is triggered, the braking system controller first executes the motor braking capability assessment process before sending a fixed braking torque request to the motor braking system.

[0175] The braking system controller sends motor status query requests to the vehicle controller at fixed intervals. In response to the query request, the vehicle controller provides feedback on the current actual available braking torque value of each wheel motor.

[0176] The actual usable braking torque of each wheel motor is affected by factors such as motor winding temperature, inverter temperature, and bus voltage. When the motor temperature rises to the protection threshold, the vehicle controller will limit the output torque of the motor to protect the motor from thermal damage. At this time, the actual usable braking torque of the motor will be lower than the rated peak torque.

[0177] The braking system controller simultaneously sends a battery status query request to the battery management system. The battery management system responds to this request by providing the current battery charging power limit. This limit is affected by the battery's state of charge (SOC) and temperature. When the SOC is higher than the high SOC threshold or the temperature is lower than the low temperature threshold, the battery management system reduces the charging power limit to protect the battery. In this case, the electrical energy generated by the motor braking cannot be fully absorbed by the battery, thus limiting the regenerative braking system's recovery capability.

[0178] The braking system controller also sends a status query request to the inverter. In response to the query request, the inverter provides feedback on the activity status of each motor speed controller. This activity status indicates whether the motor speed controller is in normal operating mode or whether there is a fault.

[0179] The braking system controller determines the maximum available braking parameters of the motor braking system based on the acquired status information.

[0180] For example, when the status information includes the available braking torque of the motor, the speed controller status, and the battery charging power limit, the braking system controller first determines the maximum available braking torque of a single wheel motor based on the actual available braking torque of each wheel motor.

[0181] Specifically, the braking system controller calculates the upper limit of the motor regenerative braking torque corresponding to the battery charging power limit based on the battery charging power limit and the motor speed at the current vehicle speed. The braking system controller compares the maximum available braking torque of a single wheel motor with the upper limit of the motor regenerative braking torque corresponding to the battery charging power limit, and takes the smaller value as the maximum available braking torque of that wheel motor in the current state.

[0182] The braking system controller also checks the speed controller status. When the speed controller status indicates that the motor speed controller is in a fault mode or inactive, the braking system controller sets the maximum available braking torque of that wheel motor to zero. The braking system controller performs the above calculations for each wheel motor separately to obtain the maximum available braking parameters for each wheel motor.

[0183] In one implementation, the braking system controller determines the target braking parameters corresponding to the current braking condition data based on the mapping relationship between braking condition data and braking parameters. The target braking parameters are the fixed regenerative braking torque values ​​of the electric motor. These fixed regenerative braking torque values ​​are determined during the vehicle development phase based on parameters such as the maximum reverse torque capability of the electric drive assembly, the maximum charging power limit of the battery system, and the maximum reverse torque impact that the suspension system can withstand. These values ​​are stored as fixed values ​​corresponding to the current vehicle model in the non-volatile memory of the braking system controller as part of the calibration parameter set.

[0184] For example, the braking system controller reads the fixed regenerative braking torque value of the motor from the calibration parameter set as the target braking parameter.

[0185] In another implementation, the braking system controller also selects one of a plurality of preset motor fixed regenerative braking torque values ​​corresponding to the current vehicle speed range as the target braking parameter based on the vehicle speed information in the current braking condition data.

[0186] The braking system controller compares the maximum available braking parameters of each wheel motor with the target braking parameters. Taking the second wheel as an example, when the maximum available braking parameters of the second wheel motor are greater than or equal to the target braking parameters, the braking system controller determines that the current recovery capability of the second wheel motor is sufficient to support the output of the target braking parameters.

[0187] The braking system controller determines the target braking parameters as the motor braking parameters when the second wheel motor braking system brakes the vehicle, and sends a braking torque request equal to the target braking parameters to the second wheel motor.

[0188] When the maximum available braking parameter of the second wheel motor is less than the target braking parameter, the braking system controller determines that the current regenerative braking capability of the second wheel motor is insufficient and cannot support the output of the target braking parameter. The braking system controller determines the maximum available braking parameter of the second wheel motor as the motor braking parameter when the second wheel motor braking system brakes the vehicle, and sends a braking torque request equal to the maximum available braking parameter to the second wheel motor.

[0189] For example, after determining the motor braking parameters of each wheel motor, the braking system controller also adjusts the compensation amount of the hydraulic braking system based on the determination results of the motor braking parameters.

[0190] For example, when the motor braking parameter of a certain wheel motor is determined to be the maximum available braking parameter of the motor and the maximum available braking parameter is less than the target braking parameter, the braking system controller calculates the difference between the target braking parameter and the maximum available braking parameter. This difference is the amount of braking torque that needs to be compensated by the hydraulic braking system.

[0191] Based on this difference, the braking system controller adds a compensation pressure to the current hydraulic braking pressure, thereby increasing the braking torque of the hydraulic braking system to compensate for the insufficient power of the electric motor.

[0192] When the status information of the motor braking system changes, such as when the available braking torque increases after the motor temperature decreases, or when the charging power limit increases after the battery state of charge changes, causing the maximum available braking parameter to increase to be greater than or equal to the target braking parameter, the braking system controller will switch the motor braking parameter from the maximum available braking parameter back to the target braking parameter and remove the compensation pressure of the hydraulic braking system accordingly.

[0193] Therefore, the selection and switching of motor braking parameters between target braking parameters and maximum available braking parameters are carried out in coordination with the compensation and adjustment of the hydraulic braking system.

[0194] The braking system controller continuously executes the aforementioned processes of motor braking capability assessment, target braking parameter determination, and motor braking parameter selection at fixed intervals. Within each control cycle, the braking system controller reacquires the state information of the motor braking system, recalculates the maximum available braking parameters for each wheel motor, and re-compares them with the target braking parameters.

[0195] When the regenerative braking capacity of the electric motor braking system changes dynamically during braking, the braking system controller reflects this change in the next control cycle and adjusts the electric motor braking parameters and hydraulic compensation pressure accordingly. Thus, the selection of electric motor braking parameters and the adjustment of hydraulic compensation are continuously updated at millisecond intervals, achieving real-time tracking and rapid response to dynamic changes in the regenerative braking capacity of the electric motor braking system.

[0196] This embodiment of the invention acquires the status information of the electric motor braking system and determines the maximum available braking parameters accordingly. The maximum available braking parameters are compared with calibrated target braking parameters. When the recovery capacity is sufficient, the target braking parameters are used to control the motor braking; when the recovery capacity is insufficient, the maximum available braking parameters are used. The hydraulic braking compensation pressure is automatically adjusted based on the deviation of the motor braking parameters. This solves the technical problem of mismatch between the fixed braking torque request and the actual available capacity when the recovery capacity dynamically changes due to factors such as temperature protection and battery state of charge changes during anti-lock braking. Therefore, the electric motor braking system always operates within the boundary of its actual available capacity, avoiding execution failures or system malfunctions caused by requests exceeding the capacity range. Furthermore, after the recovery capacity recovers, it automatically returns to the target braking parameters to maintain a fixed basic braking force platform. Thus, while ensuring system safety and reliability, it maximizes the participation ratio of the electric motor braking and achieves automatic and precise matching of hydraulic compensation.

[0197] In some embodiments of this disclosure, the electric motor braking system includes an electric motor and a battery; the vehicle includes a suspension system; and the mapping relationship between braking condition data and braking parameters is obtained based on the maximum reverse torque capability curve of the electric motor, the maximum continuous charging power of the battery, and the maximum tolerable torque impact of the suspension system under each braking condition parameter.

[0198] In this embodiment of the disclosure, for example, the mapping relationship between braking condition data and braking parameters is pre-calibrated during the vehicle development stage and stored as a calibration parameter set in the non-volatile memory of the braking system controller.

[0199] This mapping relationship is used to determine the target braking parameters of the electric motor braking system based on the current braking condition data after the anti-lock braking system is triggered. The calibration process of the mapping relationship comprehensively considers three constraints: the maximum reverse torque capability curve of the motor in the electric motor braking system, the maximum continuous charging power of the battery, and the maximum tolerable torque impact of the vehicle's suspension system.

[0200] For example, the calibration process first obtains the maximum reverse torque capability curve of the motor. The maximum reverse torque that the motor can output varies at different speeds. This capability curve is obtained through motor bench testing, recording the maximum reverse torque value corresponding to each speed point from zero speed to the maximum speed range.

[0201] In the low-speed range, the motor's back EMF is low, and the maximum reverse torque is limited by the peak winding current; in the high-speed range, the motor's back EMF increases, and the maximum reverse torque is limited by the inverter voltage limit and field weakening control capability.

[0202] This capability curve serves as the first constraint, limiting the upper limit of the maximum available braking torque of the electric motor braking system at different vehicle speeds. During calibration, the braking system controller determines the maximum reverse torque capability value of the motor at each calibration operating point based on the corresponding reference vehicle speed.

[0203] The calibration process simultaneously acquires the battery's maximum continuous charging power. During the battery design verification phase, the battery management system determines the battery's maximum continuous charging power at different states of charge and temperatures through charge-discharge tests.

[0204] When the electric motor converts the vehicle's kinetic energy into electrical energy and recharges the battery during braking, the battery's charging power limit determines the maximum electrical power that the electric motor braking system can safely regenerate. This maximum continuous charging power serves as a second constraint, limiting the upper limit of the energy recovery power of the electric motor braking system.

[0205] During the calibration process, the braking system controller divides the battery’s maximum continuous charging power by the motor speed at the current vehicle speed to obtain the upper limit of the motor’s regenerative braking torque corresponding to the battery charging power limit, and compares this upper limit of torque with the motor’s maximum reverse torque capability value.

[0206] The calibration process also obtains the maximum torsional impact that the suspension system can withstand. For example, the vehicle suspension system includes suspension brackets, suspension bushings, and suspension components connecting the motor to the vehicle frame.

[0207] When the motor outputs reverse torque, this reverse torque is transmitted to the vehicle body through the suspension system, generating impact loads on the suspension components. The maximum tolerable torque impact of the suspension system is determined through strength and fatigue durability tests on the suspension components. This value limits the stress level that the motor's reverse torque, when transmitted through the suspension system, will not cause stress levels exceeding the design limits on the suspension components. This maximum tolerable torque impact serves as a third constraint, limiting the upper limit of the maximum impact force exerted on the vehicle body structure by the reverse torque output from the motor braking system.

[0208] During the calibration process, the braking system controller comprehensively compares the torque values ​​limited by the above three constraints for each combination of braking operating condition parameters.

[0209] For example, the braking system controller obtains the maximum reverse torque capability of the motor under the current braking conditions, the upper limit of the motor regenerative braking torque corresponding to the battery charging power limit, and the maximum tolerable torque impact value of the suspension system.

[0210] The braking system controller takes the minimum of these three torque values ​​and multiplies it by a preset safety factor to obtain the calibrated motor braking parameters under this braking condition. For example, the safety factor ranges from 0.8 to 0.95, providing a safety margin for dynamic fluctuations and component performance degradation in the actual operation of the motor braking system. The braking system controller associates and stores these calibrated motor braking parameters with the braking condition parameters, forming a mapping relationship between braking condition data and braking parameters.

[0211] The calibration parameters include at least vehicle speed and braking deceleration requirements. The braking system controller performs the above calibration calculations at different vehicle speeds to obtain the calibrated motor braking parameters corresponding to different vehicle speeds.

[0212] For example, at low vehicle speeds, the maximum reverse torque capability of the motor is limited by the low back electromotive force, and the calibrated motor braking parameters are mainly determined by the motor capability curve. As the vehicle speed increases to the medium range, the maximum reverse torque capability of the motor reaches its peak, and the calibrated motor braking parameters reach their upper limit within this speed range.

[0213] For example, when the vehicle speed continues to increase to the high speed range, the motor capability curve decreases due to field weakening control. At the same time, the upper limit of torque corresponding to the battery charging power limit also decreases as the speed increases. The calibrated motor braking parameters decrease under the combined effect of these two constraints.

[0214] After calibration, the mapping relationship between braking condition data and braking parameters is stored in the braking system controller in tabular or interpolation function form.

[0215] During actual vehicle operation, when the anti-lock braking system (ABS) is triggered, the braking system controller acquires the current braking condition data, which includes at least the current vehicle speed. For example, the braking system controller uses the current vehicle speed as a query index to look up the corresponding calibrated motor braking parameters from a pre-stored mapping relationship, and uses these calibrated motor braking parameters as the target braking parameters.

[0216] The braking system controller then compares the target braking parameters with the maximum available braking parameters obtained in real time from the vehicle controller and battery management system to determine the actual motor braking parameters that are ultimately sent to the motor braking system.

[0217] Therefore, the calibration value in the mapping relationship serves as the upper limit benchmark for the target braking parameters, and is adjusted downwards according to the real-time status of the motor braking system during actual execution.

[0218] This disclosure provides a method for comprehensive calibration based on three constraints: the maximum reverse torque capability curve of the motor, the maximum continuous charging power of the battery, and the maximum tolerable torque impact of the suspension system. The minimum value among these three constraints is used as the calibrated motor braking parameters and stored as a mapping relationship between braking condition data and braking parameters. This solves the technical problem that the setting of motor braking parameters during actual operation may exceed the bearing capacity of any component of the motor, battery, or suspension system. Therefore, the calibrated motor braking parameters will not exceed the physical upper limit of the motor's reverse torque capability, the safety limit of the battery charging power, and the upper limit of the impact load that the suspension system can withstand under any braking condition. This ensures the safety and durability of the motor, battery, and suspension system simultaneously during anti-lock braking, achieving a match between the motor braking capacity and the overall vehicle load-bearing capacity.

[0219] In some embodiments of this disclosure, after controlling the vehicle to enter the anti-lock braking state, the method further includes: Update the status information of the motor braking system; Based on the updated status information, determine the updated maximum available braking parameters of the motor braking system; If the updated maximum available braking parameter is less than the motor braking parameter, the updated maximum available braking parameter shall be determined as the updated motor braking parameter. The electric motor braking system is controlled to brake the vehicle based on the updated electric motor braking parameters.

[0220] In this embodiment of the disclosure, after the anti-lock braking state is activated, the braking system controller continuously executes the update process of the motor braking system status information at a fixed period.

[0221] For example, the fixed period mentioned above is consistent with the main cycle of the anti-lock braking control, such as a fixed period of 10ms.

[0222] At the beginning of each control cycle, the braking system controller sends a status query request to the vehicle controller, battery management system and inverter to obtain the latest status information of the motor braking system at the current moment.

[0223] In response to the query request, the vehicle controller provides feedback on the actual available braking torque value of each wheel motor at the current moment. This actual available braking torque value reflects the real-time output capability of the motor under the current winding temperature, inverter temperature, and bus voltage. The battery management system, in response to the query request, provides feedback on the current battery charging power limit, which reflects the real-time charging capability of the battery under the current state of charge and temperature. The inverter, in response to the query request, provides feedback on the current activity status of each motor speed controller.

[0224] After receiving the updated status information, the braking system controller recalculates the updated maximum available braking parameters of the motor braking system based on the updated status information.

[0225] For each wheel motor, the braking system controller compares the actual available braking torque of the wheel motor with the upper limit of the motor regenerative braking torque calculated from the battery charging power limit, and takes the smaller of the two values ​​as the maximum available braking torque of the wheel motor at the current moment.

[0226] If the speed controller status of the wheel motor is in fault mode or inactive, the braking system controller sets the maximum available braking torque of that wheel motor to zero. The braking system controller performs the above calculations for each wheel motor separately to obtain the updated maximum available braking parameters for each wheel motor.

[0227] The braking system controller compares the updated maximum available braking parameters with the currently applied motor braking parameters.

[0228] Taking the second wheel as an example, the braking system controller obtains the updated maximum available braking parameters of the second wheel motor and compares the updated maximum available braking parameters with the current motor braking parameters of the second wheel motor.

[0229] The current motor braking parameters are values ​​determined and being executed in the previous control cycle. These values ​​may be equal to the target braking parameters or the maximum available braking parameters updated in the previous cycle. When the updated maximum available braking parameters are less than the current motor braking parameters, the braking system controller determines that the regenerative braking capability of the second wheel motor has decreased, and the current motor braking parameters have exceeded the actual capacity that the motor can provide.

[0230] The braking system controller determines the updated maximum available braking parameters of the second wheel motor as the updated motor braking parameters of the second wheel motor, and sends a braking torque request equal to the updated maximum available braking parameters to the second wheel motor to replace the motor braking parameters of the previous cycle.

[0231] In some implementations, the braking system controller updates the motor braking parameters and adjusts the compensation pressure of the hydraulic braking system according to the update amount of the motor braking parameters.

[0232] For example, the braking system controller calculates the difference between the target braking parameters and the updated motor braking parameters. This difference reflects the additional braking torque that the hydraulic braking system needs to bear due to the reduced braking capacity of the motor. The braking system controller converts this difference into a hydraulic braking pressure compensation amount and adds this compensation amount to the current hydraulic braking pressure, causing the hydraulic braking system to increase the corresponding braking torque to compensate for the decrease in motor power.

[0233] The braking system controller sends the updated hydraulic braking pressure command to the hydraulic braking actuator, so that the hydraulic braking system is adjusted synchronously with the updated motor braking parameters, ensuring that the total braking torque remains unchanged as the motor braking capacity decreases.

[0234] In subsequent control cycles, the braking system controller continues to perform the aforementioned process of updating status information, recalculating the maximum available braking parameters, and making comparisons and judgments.

[0235] If the condition of the motor braking system deteriorates further in subsequent cycles, resulting in a further reduction in the updated maximum available braking parameters, the braking system controller will again perform a downward adjustment of the motor braking parameters and a corresponding increase in the hydraulic compensation pressure.

[0236] If the state of the motor braking system recovers in a subsequent cycle, resulting in an increase in the updated maximum available braking parameters, the braking system controller will perform an adjustment in the opposite direction.

[0237] When the updated maximum available braking parameters are greater than or equal to the target braking parameters, the braking system controller resets the motor braking parameters to the target braking parameters and gradually removes the hydraulic compensation pressure, so that the motor braking and hydraulic braking return to the normal target distribution state.

[0238] For example, the recovery process of the motor braking parameters is carried out using a ramp function, which linearly transitions the motor braking parameters from the current value to the target braking parameters within a preset transition time window, while simultaneously linearly reducing the hydraulic compensation pressure to zero.

[0239] For example, the processes of updating the status information, recalculating the maximum available braking parameters, comparing and judging the motor braking parameters, and adjusting the hydraulic compensation pressure are continuously cyclically executed at a fixed period until the anti-lock braking state is exited.

[0240] During each control cycle, the braking system controller acquires the latest status of the motor braking system and adjusts the motor braking parameters and hydraulic compensation pressure in real time based on the latest status, so that the actual output of the motor braking system is always equal to or less than its current maximum available braking parameters, while the total braking torque remains constant.

[0241] This embodiment of the invention continuously updates the state information of the motor braking system at fixed intervals after the anti-lock braking state is activated, and recalculates the maximum available braking parameters accordingly. When the updated maximum available braking parameters are less than the current motor braking parameters, the motor braking parameters are adjusted downwards to the maximum available braking parameters. This allows the motor braking parameters to adaptively adjust with the dynamic changes in the state of the motor braking system, solving the technical problem that the fixed motor braking parameters may not match the actual capacity when the recovery capacity of the motor braking system dynamically decreases due to factors such as motor temperature rise, changes in battery state of charge, and changes in battery temperature during anti-lock braking. Therefore, the motor braking parameters adaptively adjust in real time according to the actual capacity boundary of the motor braking system, avoiding execution failures or motor overheating protection triggering due to requests exceeding the capacity range. Simultaneously, when the motor braking capacity decreases, hydraulic compensation is automatically increased to maintain a constant total braking torque. After the motor braking capacity recovers, the system automatically returns to the target braking parameters to maintain maximum energy recovery efficiency. Thus, while ensuring system safety and reliability, dynamic balance and seamless coordination of electro-hydraulic braking torque are achieved.

[0242] In some embodiments of this disclosure, after controlling the motor braking system to brake the vehicle based on the updated motor braking parameters, the method further includes: Based on the difference between the updated motor braking parameters and the original motor braking parameters, the hydraulic braking parameters are increased accordingly so that the sum of the increased hydraulic braking parameters and the updated motor braking parameters matches the target braking parameters indicated by the anti-lock braking signal.

[0243] In this embodiment of the disclosure, after the braking system controller completes the update of the motor braking parameters and sends the updated braking torque request to the motor braking system, it simultaneously executes the compensation and adjustment process of the hydraulic braking parameters.

[0244] The braking system controller acquires both the updated and previous motor braking parameters. The previous motor braking parameters were the motor braking torque values ​​determined and currently being executed in the previous control cycle. The updated motor braking parameters are the motor braking torque values ​​redefined in the current control cycle after updating the status information and comparing them with the maximum available braking parameters.

[0245] The braking system controller calculates the difference between the motor braking parameters before and after the update. When the updated motor braking parameters are less than the original motor braking parameters, the difference is positive, indicating that the motor braking system has lost braking torque equal to this difference during the current control cycle.

[0246] The braking system controller acquires the target braking parameters indicated by the anti-lock braking signal. The target braking parameters are the calibrated motor braking parameters determined by the braking system controller based on the current braking condition data and mapping relationship when anti-lock braking is triggered. These parameters serve as the target reference value for the total braking torque distribution and remain unchanged during anti-lock braking.

[0247] The braking system controller determines the required increase in hydraulic braking parameters based on the difference between the updated and unupdated motor braking parameters. This difference is then used as the target compensation for the hydraulic braking parameters, which is converted into the required increase in hydraulic braking pressure for one or more hydraulic brake actuators.

[0248] The braking system controller acquires the current hydraulic braking parameters. These parameters are the actual hydraulic braking pressure values ​​applied to each wheel at the end of the previous control cycle.

[0249] The braking system controller superimposes the current hydraulic braking parameters with the aforementioned compensation amount to obtain the improved hydraulic braking parameters. The braking system controller sends the improved hydraulic braking pressure command to the corresponding hydraulic brake actuator in the hydraulic braking system, causing the hydraulic braking system to increase the braking torque by an amount equal to the decrease in motor power on top of the current hydraulic braking pressure.

[0250] The sum of the improved hydraulic braking parameters and the updated motor braking parameters is equal to the sum of the target braking parameters indicated by the anti-lock braking signal and the current hydraulic braking parameters excluding the compensation portion. In other words, the total braking torque remains unchanged before and after the update of the motor braking parameters and is equal to the total braking torque required by the anti-lock braking signal.

[0251] When increasing hydraulic braking parameters, the braking system controller smoothly increases them according to a preset rate limit. The controller distributes the decrease in motor braking parameters according to a preset transition time window, increasing only a portion of the hydraulic braking pressure in each control cycle, so that the hydraulic braking parameters gradually increase from the current hydraulic braking parameters to the compensated target value within the transition time window.

[0252] For example, the value range of the aforementioned transition time window is 100ms to 500ms, and the specific value can be determined according to the longitudinal impact comfort threshold calibration.

[0253] In each control cycle, the braking system controller calculates the hydraulic braking pressure increment required for the current cycle, adds the increment to the current hydraulic braking pressure, and sends the updated pressure command to the hydraulic braking actuator.

[0254] At the start of the next control cycle, the braking system controller obtains the updated status information of the motor braking system again. If the motor braking parameters remain unchanged in the next cycle, the hydraulic braking parameters continue to be increased cycle by cycle according to the remaining compensation amount until all compensation amount is applied.

[0255] In some implementations, the braking system controller also monitors in real time whether the total braking torque matches the target braking parameters while increasing the hydraulic braking parameters.

[0256] The braking system controller calculates the total braking torque for each control cycle. This total braking torque is equal to the sum of the updated motor braking parameters and the improved hydraulic braking parameters for the current cycle. The braking system controller then compares the calculated total braking torque with the target braking parameters indicated by the anti-lock braking signal.

[0257] When the deviation between the total braking torque and the target braking parameter is less than the preset deviation threshold, the braking system controller determines that the total braking torque has matched the target braking parameter and stops further increasing the hydraulic braking parameter.

[0258] When the deviation between the total braking torque and the target braking parameter is greater than or equal to the preset deviation threshold, the braking system controller continues to perform the hydraulic braking parameter increase operation in the next control cycle until the deviation is reduced to within the deviation threshold.

[0259] Therefore, by using closed-loop monitoring and cycle-by-cycle approximation, the total braking torque is ultimately ensured to accurately match the target braking parameters.

[0260] For example, the process of increasing the hydraulic braking parameters is synchronized with the updating of the motor braking system status information and the adaptive adjustment of the motor braking parameters. When the motor braking capacity decreases, the motor braking parameters are adjusted downwards, and the hydraulic braking parameters are simultaneously compensated upwards; when the motor braking capacity recovers, the motor braking parameters return to their original position, and the hydraulic braking parameters are simultaneously removed downwards. Throughout the entire process, the motor braking parameters and the hydraulic braking parameters change in a mirror-symmetric manner, and the total braking torque remains constant.

[0261] This embodiment of the invention calculates the difference between the updated and unupdated motor braking parameters and increases the hydraulic braking parameters accordingly. This ensures that the sum of the increased hydraulic braking parameters and the updated motor braking parameters always matches the target braking parameters indicated by the anti-lock braking signal. This solves the technical problem of fluctuations in total braking torque due to changes in motor capability during the adaptive adjustment of motor braking parameters. Therefore, when the motor braking capability decreases, the hydraulic braking system automatically assumes the lost braking torque; when the motor braking capability recovers, the hydraulic braking system automatically relinquishes the braking torque. The total braking torque remains constant throughout the dynamic change of motor braking capability, perfectly matching the driver's braking request. This avoids sudden changes in braking deceleration caused by fluctuations in braking torque, thus ensuring the smoothness and consistency of the braking process while achieving adaptive adjustment of motor braking parameters. This allows occupants to experience the dynamic switching and compensation of electro-hydraulic braking torque without any noticeable impact.

[0262] In some embodiments of this disclosure, exemplarily, Figure 2 A flowchart illustrating a method for triggering an anti-lock braking signal according to some embodiments of this disclosure is shown, such as... Figure 2 As shown, the method also includes: S202, upon receiving a braking operation, determines the target deceleration and the rate of change of the target deceleration as indicated by the braking operation.

[0263] In this embodiment of the disclosure, the braking system controller continuously monitors the driver's braking operations at fixed intervals during vehicle operation.

[0264] For example, the brake system controller acquires the brake pedal travel signal in real time through a brake pedal displacement sensor.

[0265] For example, a brake pedal displacement sensor is mounted on the brake pedal assembly to convert the mechanical displacement of the brake pedal into an electrical signal, which is then output to the brake system controller. Upon receiving the electrical signal from the brake pedal displacement sensor, the brake system controller filters the signal to eliminate high-frequency noise and spike interference that may be introduced during signal transmission.

[0266] The braking system controller obtains the target deceleration value and target deceleration rate of the driver's braking operation instruction by analyzing the filtered electrical signal.

[0267] The target deceleration value represents the magnitude of the braking deceleration that the driver expects the vehicle to achieve at the current moment. The target deceleration rate of change represents the speed at which the driver depresses the brake pedal, i.e., the urgency of the driver's braking intention.

[0268] S204, when the target deceleration is greater than the deceleration threshold and the rate of change of the target deceleration is greater than the rate of change threshold, the anti-lock braking signal is triggered.

[0269] In this embodiment of the present disclosure, the braking system controller compares the target deceleration value obtained by parsing with a preset deceleration threshold.

[0270] For example, the deceleration threshold is a pre-calibrated fixed value used to distinguish between normal braking and emergency braking.

[0271] For example, the deceleration threshold is calibrated to 0.5g, which is 0.5 times the acceleration due to gravity. The deceleration threshold corresponds to the minimum deceleration request level required to trigger the anti-lock braking system.

[0272] When the target deceleration value is less than or equal to the deceleration threshold, the braking system controller determines that the current braking operation falls within the scope of normal braking and does not trigger the anti-lock braking signal. The vehicle then performs braking control according to the normal cooperative regenerative braking process. When the target deceleration value is greater than the deceleration threshold, the braking system controller enters the first level of emergency braking prediction state.

[0273] The braking system controller compares the target deceleration rate obtained from the analysis with a preset rate of change threshold.

[0274] The rate of change threshold is a pre-calibrated fixed value used to identify whether the driver depresses the brake pedal at an extremely high speed. For example, the rate of change threshold is 200 g / s, or 200 times the acceleration due to gravity per second. This threshold corresponds to the typical operating rate at which a driver rapidly depresses the brake pedal in an emergency avoidance maneuver.

[0275] When the target deceleration rate of change is less than or equal to the rate of change threshold, the braking system controller will not trigger the anti-lock braking signal even if the target deceleration value has exceeded the deceleration threshold. This situation corresponds to a situation where the driver applies a large braking deceleration request, but the brake pedal is pressed relatively smoothly, such as when the driver continuously applies large braking force on a long downhill section but it is not an emergency avoidance scenario.

[0276] At this point, the vehicle continues to be controlled according to the conventional braking procedure. When the target deceleration rate of change exceeds the rate of change threshold, the braking system controller enters the second-level predictive state of emergency braking.

[0277] When both the target deceleration value and the target deceleration rate of change are met, the braking system controller triggers the anti-lock braking signal.

[0278] For example, the braking system controller sets the internally stored emergency braking flag to an active state, which is used to indicate the activation of the anti-lock braking control logic.

[0279] In some implementations, to avoid the anti-lock braking function being falsely triggered due to transient noise in the sensor signal or brief driver misoperation, the brake system controller does not immediately trigger the anti-lock braking signal after determining that both conditions are met, but instead starts an anti-shake timing mechanism.

[0280] The braking system controller resets the emergency braking preparation counter to zero and reacquires the target deceleration value and target deceleration rate of change in each subsequent acquisition cycle, comparing them again with the deceleration threshold and rate of change threshold.

[0281] The braking system controller only confirms the emergency braking state when the target deceleration value is greater than the deceleration threshold and the target deceleration rate of change is greater than the rate of change threshold for multiple consecutive acquisition cycles.

[0282] For example, the continuous judgment cycle is three cycles, each cycle being 10ms. That is, after the emergency braking conditions are met for 30 consecutive ms, the braking system controller finally triggers the anti-lock braking signal. The anti-shake timing mechanism effectively eliminates false triggers caused by instantaneous fluctuations in sensor signals or unconscious rapid taps of the pedal by the driver, improving the accuracy and reliability of emergency braking judgment.

[0283] Upon triggering of the anti-lock braking signal, the braking system controller performs the following actions according to the methods described in the preceding embodiments: requesting a fixed braking torque from the electric motor, dynamically adjusting the hydraulic system, assessing the motor's braking capacity, adaptively updating the motor's braking parameters, and synchronously compensating for the hydraulic braking parameters. During the activation of the anti-lock braking signal, the braking system controller continuously monitors changes in the driver's braking operation signals.

[0284] When the braking system controller detects that the target deceleration value has decreased to less than or equal to the deceleration threshold, and this state persists for a preset exit time window, the braking system controller determines that the driver's emergency braking request has ended. The exit time window can be set to 500ms. When the exit conditions are met, the braking system controller clears the emergency braking flag, controls the vehicle to exit the anti-lock braking state, and restores the normal cooperative regenerative braking control mode.

[0285] This embodiment of the disclosure simultaneously monitors the target deceleration value and the target deceleration rate of change upon receiving a braking operation. It triggers the anti-lock braking signal only when the target deceleration value exceeds a deceleration threshold and the target deceleration rate of change exceeds a rate of change threshold. Furthermore, it incorporates an anti-shake judgment mechanism before triggering the signal. This addresses the technical problems of response delays that may arise from relying solely on deceleration amplitude in emergency braking scenarios, as well as the false triggering of the anti-lock braking function due to sensor signal noise or driver error. Therefore, through parallel judgment of dual conditions, this method can promptly trigger the anti-lock braking function in emergency avoidance scenarios where the driver rapidly and deeply depresses the brake pedal. Simultaneously, it avoids false triggering of the anti-lock braking function in non-emergency braking scenarios such as gentle braking on long downhill slopes, achieving a balance between the timeliness of emergency braking response and the accuracy of anti-lock braking function triggering. This improves the intelligence level of the anti-lock braking system and driving safety.

[0286] In some embodiments of this disclosure, the method further includes: If the target deceleration remains less than or equal to the deceleration threshold during the first duration, or if the vehicle speed is less than the speed threshold, the vehicle is controlled to exit the anti-lock braking state, and the motor braking parameters are gradually reduced to 0 during the second duration, while the hydraulic braking parameters are gradually increased to the total braking parameters indicated by the braking operation.

[0287] In this embodiment of the disclosure, the braking system controller continuously executes a monitoring process for exit conditions during the activation of the anti-lock braking signal.

[0288] For example, the braking system controller acquires the target deceleration value indicated by the driver's braking operation in each control cycle and compares this target deceleration value with a deceleration threshold. Simultaneously, the braking system controller acquires wheel speed signals from the wheel speed sensors and calculates a reference vehicle speed as the vehicle's travel speed based on these wheel speed signals. The braking system controller then compares the calculated travel speed with a preset speed threshold.

[0289] The speed threshold is a pre-calibrated fixed value used to determine whether the vehicle is close to stopping. For example, the speed threshold ranges from 10 km / h to 40 km / h. For instance, the speed threshold could be 30 km / h.

[0290] The braking system controller monitors the duration for which the target deceleration value exceeds the deceleration threshold and maintains an exit timer internally.

[0291] When the target deceleration value is greater than the deceleration threshold, the timer exits, is reset to zero, and remains at zero.

[0292] When the target deceleration value first decreases to less than or equal to the deceleration threshold, the exit timer starts counting from zero. During the exit timer's timing, the braking system controller reacquires the target deceleration value in each control cycle and compares it with the deceleration threshold.

[0293] If the target deceleration value exceeds the deceleration threshold again during any control cycle in the timing period, the timer will be immediately reset to zero, and the exit condition will be determined as not being met.

[0294] If the timeout period reaches the first duration and the target deceleration value is always less than or equal to the deceleration threshold during this period, the braking system controller determines that the driver has released the emergency braking request, thus satisfying the first exit condition.

[0295] For example, the first duration ranges from 100ms to 1000ms. For instance, the first duration is 500ms. This value ensures that the driver has indeed released the brake pedal after emergency braking, rather than experiencing a brief pedal jitter or pressure fluctuation.

[0296] The braking system controller also monitors the vehicle's speed. When the vehicle's speed decreases to below a speed threshold, the braking system controller determines that the vehicle is close to stopping, thus meeting the second exit condition.

[0297] At extremely low vehicle speeds, the signal-to-noise ratio of wheel speed signals decreases, and the accuracy of wheel speed measurement is reduced. At this time, the reliability of motor regenerative braking participating in slip ratio regulation decreases, and the vehicle is more sensitive to fluctuations in braking torque at low speeds.

[0298] When either the first or second exit condition is met, the brake system controller controls the vehicle to exit the anti-lock braking state. The brake system controller clears the emergency braking flag and switches the control mode from anti-lock braking state to conventional braking state.

[0299] During the exit process, the braking system controller acquires the total braking parameters of the current braking operation instruction, which is the total braking torque requested by the driver through the brake pedal at that moment. The braking system controller also acquires the current motor braking parameters of the electric motor braking system and the hydraulic braking parameters of the hydraulic braking system, which are the values ​​being executed at the time of the exit trigger.

[0300] The braking system controller gradually reduces the motor braking parameters from their current value to zero within the second time period, while simultaneously gradually increasing the hydraulic braking parameters from their current value to the total braking parameters indicated by the braking operation.

[0301] For example, the second duration is a pre-calibrated transition time window, with a value ranging from 100ms to 300ms. During the second duration, the braking system controller synchronizes the decrease of the motor braking parameters with the increase of the hydraulic braking parameters, ensuring that the algebraic sum of the two is always equal to the total braking parameters indicated by the braking operation.

[0302] For example, the braking system controller will uniformly reduce the motor braking parameters from their current values ​​to zero within a second time period according to a linear decreasing function, and uniformly increase the hydraulic braking parameters from their current values ​​to the total braking parameters within a second time period according to a linear increasing function.

[0303] Within each control cycle, the braking system controller calculates the decrease in motor braking parameters and the increase in hydraulic braking parameters based on the time remaining from the current time to the exit trigger time. The controller then sends the calculated motor braking parameter command to the motor braking system and the calculated hydraulic braking parameter command to the hydraulic braking system, enabling both systems to synchronously transition within the second time period.

[0304] As the motor braking parameters gradually decrease, the braking system controller continuously monitors the status information of the motor braking system. If, during a control cycle within the second time period, the maximum available braking parameter of the motor braking system is detected to be less than the motor braking parameter of the current command, the braking system controller immediately adjusts the motor braking parameter downward to the maximum available braking parameter and correspondingly increases the rate of increase of the hydraulic braking parameter to ensure that the total braking torque always matches the total braking parameter indicated by the braking operation.

[0305] When the second duration ends and the motor braking parameters have decreased to zero, the braking system controller determines that the motor braking has been completely disengaged, and the vehicle's braking torque is entirely borne by the hydraulic braking system. The control mode is then completely switched to the conventional hydraulic braking mode.

[0306] In some implementations, when the exit condition is triggered by the second exit condition, i.e., when the vehicle speed is less than a speed threshold, the brake system controller also executes the electro-hydraulic transition process within the aforementioned second duration. When the vehicle speed has dropped below the speed threshold, the process of decreasing the electric motor braking parameters and increasing the hydraulic braking parameters are also executed step-by-step according to the second duration, ensuring a transition buffer period is maintained before the electric motor braking completely disengages, thus guaranteeing the smoothness of the braking torque when the vehicle is about to stop.

[0307] This embodiment solves the technical problems of sudden drop in braking torque, sudden change in vehicle deceleration, and resulting vehicle pitching impact caused by sudden withdrawal of motor braking during anti-lock braking by controlling the vehicle to exit the anti-lock braking state when the target deceleration is continuously less than or equal to the deceleration threshold for a first time period, or when the vehicle speed is less than the speed threshold. It also solves these problems by gradually reducing the electric motor braking parameters to zero and gradually increasing the hydraulic braking parameters to the total braking parameters indicated by the braking operation during a second time period. As a result, the electric motor braking and hydraulic braking synchronously and smoothly switch torque according to a preset transition time window during the withdrawal process. The total braking torque remains constant and matches the driver's braking request throughout the entire process of electric motor braking withdrawal, avoiding sudden changes in braking deceleration and eliminating the vehicle impact and jerking sensation caused by sudden withdrawal of electric motor braking. This achieves a seamless and imperceptible switch between electro-hydraulic braking when the anti-lock braking function is deactivated, improving the smoothness of the braking process and driving comfort.

[0308] In one specific embodiment, the braking control method includes the following specific steps: 1. Driver's braking intent is collected.

[0309] The braking system controller (ESP or IPB) collects the driver's brake pedal signal in real time through the brake pedal displacement sensor, and analyzes it to obtain the driver brake request (DBR), which includes the target deceleration value a_req and the deceleration rate of change da / dt.

[0310] 2. Emergency braking determination.

[0311] The braking system controller operates the emergency braking determination module to determine whether the current DBR meets the emergency braking trigger conditions: (1) Deceleration amplitude determination: a_req>A_THRESHOLD. Wherein, A_THRESHOLD is the preset emergency braking deceleration threshold value, such as 0.5g, which can be calibrated according to the vehicle model; (2) Determination of deceleration rate of change: da / dt>D_THRESHOLD. Wherein, D_THRESHOLD is the preset threshold value of the rate of change, such as 200g / s, which can be calibrated according to the vehicle model.

[0312] When conditions (1) and (2) are met simultaneously, the current state is determined to be an emergency braking trigger state, and the emergency braking flag E-ABS_Active=TRUE is set; otherwise, the normal braking process (CRBS cooperative regenerative braking) is followed.

[0313] 3. Constant voltage value calibration query and motor braking capability assessment.

[0314] After emergency braking is triggered, the braking system controller, based on the current vehicle configuration, queries the calibration parameter set for the preset constant value TqElecFixed, which is the fixed regenerative braking torque value that each wheel motor should request. This constant value is determined during the vehicle development phase through the following parameter calibration: (1) Maximum reverse torque capability of electric drive assembly, such as the maximum reverse torque capability of DHT260 is -3100Nm, and the maximum reverse torque capability of NDE34 is -3100Nm; (2) Maximum charging power limit of battery system (P_charge_max); (3) The maximum reverse torque impact that the suspension system can withstand; (4) Vehicle parameters such as overall vehicle weight and tire rolling radius.

[0315] The calibrated constant voltage value corresponds to the maximum motor braking deceleration (e.g., 0.6g), and can be calibrated differently according to the tolerance of different vehicle architectures. At the same time, the braking system controller requests the current actual available braking torque range of each drive motor from the Vehicle Control Unit (VCU), obtains the current battery charging power limit from the Battery Management System (BMS), and obtains the activity status of each motor speed controller from the Inverter (INV), and comprehensively evaluates whether the current motor / battery system supports the full execution of the constant voltage value.

[0316] 4. Fixed electro-hydraulic control strategy execution, i.e., braking torque distribution.

[0317] The braking system controller operates the constant electro-hydraulic strategy module, distributing braking torque according to the following logic: (1) Motor setting request: Send a fixed braking torque request TqElecFixed (fixed value) to each wheel motor. This value remains constant throughout the emergency braking process. (2) Hydraulic dynamic adjustment: The hydraulic braking system dynamically compensates and adjusts the braking pressure of each wheel according to the following real-time parameters: a. Road surface adhesion coefficient μ: The VSE module estimates the road surface adhesion coefficient of each wheel in real time based on the wheel speed signal and the 6DIMU signal. When the road surface adhesion coefficient of a certain wheel is low, the hydraulic braking pressure of that wheel is reduced to prevent it from locking up. b. Vehicle dynamic status: The VSE module provides 6D status information such as longitudinal / lateral acceleration, yaw rate, and roll rate. When it detects that the vehicle has a tendency to fishtail (yaw rate exceeds the limit) or a large load transfer (longitudinal acceleration exceeds the limit), it dynamically adjusts the hydraulic braking pressure distribution of the front and rear axles and the left and right wheels to maintain vehicle stability. c. Slip ratio deviation: Based on the deviation between the target slip ratio (optimal range of 10%~20%) of each wheel calculated by VSE and the actual slip ratio, closed-loop adjustment is preferentially performed by hydraulic brake pressure modulation.

[0318] (3) Total braking torque is satisfied: If the fixed torque of the motor TqElecFixed cannot meet the total target braking torque requirement, the hydraulic braking system will automatically make up the difference in braking force to ensure that the total braking torque does not decrease.

[0319] 5. Precise control of ABS slip ratio The braking system controller calculates the actual slip ratio of each wheel in real time based on the target slip ratio (optimal range of 10%~20%) provided by the VSE. Under the constant electro-hydraulic strategy, slip ratio control is mainly achieved through hydraulic brake pressure modulation (with motor torque kept constant). By adjusting the hydraulic brake pressure at high frequency (approximately 5ms / time, 200Hz), the slip ratio of each wheel is precisely controlled within the target range to prevent wheel lock-up.

[0320] 6. Real-time monitoring of motor / battery recycling capabilities and seamless electro-hydraulic switching.

[0321] During motor braking, the braking system controller continuously monitors the following states at millisecond-level frequencies: (1) The actual available braking torque (TqMinElec) of each wheel motor fed back by VCU is used to determine whether the available torque has decreased due to motor temperature protection, winding overheating, or other reasons. (2) The INV feedback of the speed controller activity status (RpmCtrlAct) is used to determine whether the motor speed control is normal; (3) The upper limit of battery charging power (P_charge_max) fed back by BMS is used to determine whether the battery is limiting its charging power due to excessive SOC or abnormal temperature.

[0322] When insufficient motor / battery regeneration capacity is detected (i.e., actual available braking torque < constant value TqElecFixed), the braking system controller immediately and dynamically adjusts the braking force distribution: maintaining the motor at its current maximum available torque for braking, while simultaneously increasing hydraulic braking pressure to compensate for the braking force difference ΔTq = TqElecFixed - TqMinElec_actual, ensuring that the total braking torque does not decrease. This switching process is seamless and imperceptible to the occupants. Once the regeneration capacity is restored, the motor torque returns to the constant value, and the hydraulic braking pressure decreases accordingly.

[0323] 7. Low-speed exit strategy When the vehicle speed drops to a preset low-speed threshold (e.g., 30 km / h, depending on the vehicle model), the electric motor braking torque linearly decreases from the fixed value TqElecFixed to zero, while the hydraulic braking torque increases linearly to compensate for the braking force, ensuring a smooth transition of the total braking torque. When the vehicle speed drops to approximately 5 km / h or the vehicle comes to a complete stop, the electric motor braking completely disengages, and the hydraulic braking independently completes the final braking stop, ensuring braking stability and safety under low-speed conditions.

[0324] Specifically, the detailed process of the emergency braking judgment logic is as follows: 1. The brake system controller collects the brake pedal displacement sensor signal in real time at a fixed period (e.g., 10ms), and after filtering, it analyzes and obtains the current DBR: deceleration request value a_req and deceleration change rate da / dt.

[0325] 2. Compare a_req with the preset emergency braking deceleration threshold value A_THRESHOLD (calibrated value, such as 0.5g). If a_req≤A_THRESHOLD, maintain normal braking and do not trigger emergency braking.

[0326] 3. Compare da / dt with the preset rate of change threshold D_THRESHOLD (calibrated value, such as 200g / s). If da / dt ≤ D_THRESHOLD, maintain normal braking.

[0327] 4. When both a_req>A_THRESHOLD and da / dt>D_THRESHOLD are satisfied, it is determined that emergency braking has been triggered, and the emergency braking flag E-ABS_Active=TRUE is set.

[0328] 5. To avoid false triggering, an anti-shake mechanism is added: the emergency braking state is finally confirmed only after the emergency braking conditions are met for N consecutive cycles (e.g., 3 cycles, i.e., 30ms).

[0329] 6. After emergency braking is activated, continuously monitor the DBR signal. If a_req drops below A_THRESHOLD and continues for the preset exit time (e.g., 500ms), then the emergency braking is considered to have ended, E-ABS_Active=FALSE is set, this method is exited, and normal braking control is restored.

[0330] During the constant-torque phase, the motor's constant torque request includes: 1. After emergency braking is triggered, the braking system controller immediately reads the current vehicle model's set electrical value TqElecFixed from the vehicle model calibration parameter set.

[0331] 2. Calibration method for the constant voltage value TqElecFixed: a. Obtain the maximum reverse torque capability curve of the electric drive assembly in each speed range (TqMotorMax(n)); b. Obtain the maximum continuous charging power P_charge_max provided by the battery management system; c. Obtain the maximum reverse torque impact that the suspension system can withstand, TqMountMax; d. Considering the above constraints, calculate the constant voltage values ​​of each wheel motor: TqElecFixed = min(TqMotorMax(n), P_charge_max / ω, TqMountMax) × safety factor (e.g., 0.9); e. Convert TqElecFixed to the equivalent deceleration aElecFixed (e.g., 0.6g) and store it as a vehicle calibration parameter.

[0332] 3. The braking system controller sends a fixed braking torque request command for each wheel motor to the VCU. The request value is TqElecFixed.

[0333] 4. Throughout the entire emergency braking process (from triggering to low-speed exit), TqElecFixed remains constant and does not adjust with changes in road adhesion coefficient, vehicle dynamics, slip ratio, or other operating conditions.

[0334] During the fluid control phase, the hydraulic braking is dynamically adjusted, specifically including: 1. The hydraulic braking system receives dynamic adjustment commands from the braking system controller and makes real-time adjustments based on the following three types of parameters: (1) Hydraulic adjustment based on road surface adhesion coefficient: The VSE module uses wheel speed sensor signals and 6DIMU signals to estimate the road adhesion coefficient μ_i (i=FL,FR,RL,RR) of each wheel's grid in real time using a Kalman filter algorithm. The braking system controller dynamically adjusts the hydraulic braking pressure of each wheel based on the μ_i value. High-adhesion road surfaces (μ>0.8): Hydraulic braking can withstand greater pressure, and in conjunction with motor setpoints, it can meet the requirements for high deceleration; Medium adhesion road surface (0.4 < μ ≤ 0.8): Hydraulic braking is moderately reduced, and motor-driven fixed-value braking is the main method; Low-adhesion road surfaces (μ≤0.4): Hydraulic braking significantly reduces wheel lock-up, while motor-driven constant-value braking provides stable deceleration.

[0335] (2) Hydraulic adjustment based on vehicle body dynamics: The VSE module provides 6D vehicle status information, including longitudinal acceleration ax, lateral acceleration ay, vertical acceleration az, yaw rate ωz, pitch rate ωy, and roll rate ωx. The braking system controller dynamically distributes hydraulic pressure according to the following rules: Longitudinal load transfer: When a large longitudinal deceleration (ax increases negatively) is detected, the front axle load increases and the rear axle load decreases. The hydraulic braking pressure is tilted towards the front axle (increasing the front axle hydraulic pressure and decreasing the rear axle hydraulic pressure) to make full use of the front axle's higher adhesion. Lateral stability: When the yaw rate ωz exceeds the preset threshold, it is determined that the vehicle has a tendency to fishtail or skid. The braking system controller generates a reverse yaw moment by differentially adjusting the hydraulic braking pressure of the left and right wheels (increasing the braking force of the outer wheel and decreasing the braking force of the inner wheel) to suppress vehicle instability. Roll control: When a large roll rate ωx is detected, the vehicle body attitude is assisted by adjusting the hydraulic braking pressure distribution between the left and right wheels.

[0336] (3) Hydraulic regulation based on slip ratio: The VSE module calculates the actual slip ratio λ_i of each wheel in real time based on the wheel speed and the reference vehicle speed. The braking system controller compares λ_i with the target slip ratio range (10%~20%). If λ_i > 20% (the wheel tends to lock up): reduce the slip ratio by decreasing the hydraulic braking pressure of that wheel; If λ_i < 10% (insufficient braking): improve braking efficiency by increasing the hydraulic braking pressure of that wheel; If 10%≤λ_i≤20% (optimal range): keep the current hydraulic braking pressure unchanged.

[0337] The slip ratio adjustment adopts PID closed-loop control, with hydraulic braking pressure as the adjustment quantity (motor torque remains constant), and the adjustment frequency is about 5ms / time (200Hz) to ensure that the slip ratio of each wheel is always maintained in the optimal range.

[0338] For electro-hydraulic coordinated monitoring and switching: 1. The braking system controller executes the following monitoring cycle at a fixed period (e.g., 10ms): a. Obtain the current actual available braking torque TqMinElec_actual for each wheel motor from the VCU; b. Obtain the current battery charging power limit P_charge_max from the BMS; c. Obtain the activity status of each motor speed controller RpmCtrlAct from INV.

[0339] 2. Calculate the deviation between the motor's usable torque and its rated value: ΔTq=TqElecFixed-TqMinElec_actual.

[0340] 3. If ΔTq>0 (insufficient motor recovery capacity), the braking system controller calculates the braking torque ΔTq_hyd=ΔTq that needs hydraulic compensation, and distributes ΔTq_hyd to the hydraulic brake actuators of each wheel according to the front and rear axle braking force distribution ratio, increasing the corresponding hydraulic braking pressure.

[0341] 4. If ΔTq≤0 (motor recovery capacity is sufficient), maintain the constant voltage value and adjust the hydraulic braking pressure normally according to the "hydraulic control" logic.

[0342] 5. When the motor recovery capability is restored (TqMinElec_actual≥TqElecFixed).

[0343] The following examples illustrate this point: Scenario 1: High-adhesion uniform road surface (such as dry asphalt road surface, μ≈0.9, deceleration requirement of more than 1.0g).

[0344] The electric motor maintains its maximum braking capacity (e.g., 0.6g) with a fixed value, while the hydraulic brake dynamically compensates for the remaining amount (approximately 0.4g) based on the total deceleration requirement. Due to the high and uniform road surface adhesion coefficient, the hydraulic brake pressure adjustment range is small, making it easy to control the slip ratio of each wheel within the optimal range.

[0345] Scenario 2: Split road surface (left side high adhesion μ≈0.8, right side low adhesion μ≈0.3).

[0346] The electric motor applies constant braking force evenly to both left and right wheels, while the hydraulic braking system differentially adjusts based on the difference in road surface adhesion coefficients between the left and right wheels: the hydraulic braking pressure on the low-adhesion side (right) is significantly reduced to prevent wheel lock-up, while the hydraulic braking pressure on the high-adhesion side (left) is appropriately increased to compensate for the total braking force. Simultaneously, the difference in braking force between the left and right wheels generates a counter-yawing moment to suppress vehicle yaw.

[0347] Scenario 3: Connecting road surface (from high adhesion μ≈0.8 to low adhesion μ≈0.2).

[0348] The motor maintains a constant braking value. When the road surface adhesion coefficient changes abruptly, the VSE module quickly identifies the change in μ value (response time <50ms), and the hydraulic braking system immediately reduces the braking pressure of the corresponding wheel to prevent wheel lock-up due to a sudden drop in adhesion coefficient. The motor's constant value can still provide stable braking deceleration on low-adhesion roads without causing wheel lock-up.

[0349] Scenario 4: Emergency braking is accompanied by a significant load transfer (such as high-speed emergency braking, where the front axle load increases significantly).

[0350] With the motor's fixed braking value remaining unchanged, the hydraulic braking system dynamically increases the front axle hydraulic braking pressure (fully utilizing the increased adhesion of the front axle) and decreases the rear axle hydraulic braking pressure (preventing the rear axle from locking up prematurely due to reduced load) based on the longitudinal acceleration changes detected by VSE, thus achieving optimal distribution of braking force between the front and rear axles.

[0351] Scenario 5: Emergency braking on a curve (with lateral acceleration during braking).

[0352] The motor's fixed braking value remains unchanged. The hydraulic braking system, based on the yaw rate and lateral acceleration detected by VSE, differentially adjusts the hydraulic braking pressure of the left and right wheels to provide braking deceleration while generating a reverse yaw torque. This suppresses the vehicle's tendency to oversteer or understeer, ensuring stability during emergency braking in curves.

[0353] In some embodiments, different constant voltage values ​​are used in different vehicle speed ranges. For example, a higher constant voltage value (e.g., 0.6g) is used in the high-speed range (>80km / h), a medium constant voltage value (e.g., 0.4g) is used in the medium-speed range (40~80km / h), and a lower constant voltage value (e.g., 0.2g) is used in the low-speed range (<40km / h) to adapt to the torque output characteristics and NVH requirements of the motor at different vehicle speeds. This alternative can further optimize the NVH performance in the low-to-medium speed range while ensuring braking performance.

[0354] In some embodiments, a higher constant voltage is used when the battery SOC is low (e.g., <80%) to maximize energy recovery, and a lower constant voltage is used when the battery SOC is high (e.g., >90%) to protect the battery, with any shortfall supplemented by hydraulic braking. This alternative adds a dimension to battery life protection.

[0355] In some embodiments, different constant voltage calibration gears are switched according to the driving mode selected by the driver (such as Sport mode, Comfort mode, and Eco mode). Sport mode uses a higher constant voltage to ensure braking response, Eco mode uses the highest constant voltage to maximize energy recovery, and Comfort mode uses a moderate constant voltage to optimize NVH performance.

[0356] In some embodiments of this disclosure, an anti-lock braking control device for a vehicle is also provided. The vehicle includes an electric braking system and a hydraulic braking system.

[0357] For example, Figure 3 Structural block diagrams of anti-lock braking control devices according to some embodiments of this disclosure are shown, such as... Figure 3 As shown, the anti-lock braking control device 300 includes: a control module 302, an acquisition module 304, and an adjustment module 306.

[0358] Control module 302 is used to control the vehicle to enter the anti-lock braking state in response to the triggered anti-lock braking signal; in the anti-lock braking state, the electric braking system and the hydraulic braking system work together to brake the vehicle; The acquisition module 304 is used to acquire the vehicle's braking condition data; The adjustment module 306 is used to adjust the hydraulic braking parameters of the hydraulic braking system when braking the vehicle based on braking condition data.

[0359] This embodiment of the invention utilizes a motor braking system that participates in anti-lock braking with a fixed torque, and a hydraulic braking system that dynamically adjusts the braking parameters of each wheel based on braking condition data. This reduces the workload of the hydraulic pump and solenoid valve body in the hydraulic braking system by frequently adjusting them, thereby reducing the high-frequency operating noise and mechanical vibration generated during the operation of the hydraulic braking system, reducing the high-frequency friction loss between the brake disc and the friction pads, extending the service life of the core components of the braking system, and realizing the recovery and utilization of braking energy. Furthermore, by real-time monitoring of the motor braking recovery capability and hydraulic compensation, seamless integration of electro-hydraulic braking is achieved. Thus, while ensuring braking safety and vehicle stability, it improves driving comfort and energy recovery efficiency.

[0360] In some embodiments of this disclosure, an electronic device is also provided, exemplarily, Figure 4 Structural block diagrams of electronic devices according to some embodiments of the present disclosure are shown, such as Figure 4 As shown, the electronic device 400 includes: Memory 402, processor 404, and computer program 406; The computer program 406 is stored in the memory 402 and configured to be executed by the processor 404 to implement the anti-lock braking control method provided in any of the above embodiments. Therefore, all the same technical effects can be achieved, and to avoid repetition, they will not be described again here.

[0361] In some embodiments of this disclosure, a computer-readable storage medium is also provided, on which a computer program is stored. When executed by a processor, the computer program implements the anti-lock braking control method provided in any of the above embodiments. Therefore, all the same technical effects can be achieved, and to avoid repetition, further details are omitted here.

[0362] In some embodiments of this disclosure, a vehicle is also provided, including: an electronic device as described in any of the foregoing embodiments; and / or a computer-readable storage medium as described in any of the foregoing embodiments. Therefore, all the same technical effects can be achieved, and to avoid repetition, further details are omitted here.

[0363] It should be noted that, in this document, relational terms such as "first" and "second" are used merely 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.

[0364] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for anti-lock braking control of a vehicle, characterized in that, The vehicle includes an electric braking system and a hydraulic braking system; the method includes: In response to a triggered anti-lock braking signal, the vehicle is controlled to enter an anti-lock braking state; in the anti-lock braking state, the electric braking system and the hydraulic braking system work together to brake the vehicle; Obtain the braking condition data of the vehicle; Based on the braking condition data, only the hydraulic braking parameters of the hydraulic braking system when braking the vehicle are adjusted.

2. The method according to claim 1, characterized in that, The braking condition data includes at least one of the following: the road adhesion coefficient corresponding to the wheel, the vehicle acceleration, the vehicle yaw rate, the vehicle roll rate, and the wheel slip ratio. The step of adjusting the hydraulic braking parameters of the hydraulic braking system when braking the vehicle based on the braking condition data includes: If the road surface adhesion coefficient corresponding to the first wheel is less than a first threshold, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the first wheel; and / or, When the vehicle body angular velocity is greater than the second threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the front wheels and the hydraulic braking parameters of the hydraulic braking system corresponding to the rear wheels; and / or, If the vehicle body yaw rate is greater than a third threshold, or if the vehicle body tilt rate is greater than a fourth threshold, adjust the distribution ratio of the hydraulic braking parameters of the hydraulic braking system corresponding to the left wheel and the hydraulic braking parameters of the hydraulic braking system corresponding to the right wheel; and / or, The hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel are adjusted based on the wheel slip ratio of the second wheel so that the wheel slip ratio of the second wheel matches the target slip ratio range.

3. The method according to claim 2, characterized in that, The maximum value of the target slip ratio range is the first slip ratio, and the minimum value of the target slip ratio range is the second slip ratio; The adjustment of the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel based on the wheel slip ratio of the second wheel, so that the wheel slip ratio of the second wheel matches the target slip ratio, includes: If the wheel slip ratio corresponding to the second wheel is greater than the first slip ratio, reduce the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio corresponding to the second wheel falls into the target slip ratio range; Alternatively, if the wheel slip ratio corresponding to the second wheel is less than the second slip ratio, increase the hydraulic braking parameters of the hydraulic braking system corresponding to the second wheel until the wheel slip ratio corresponding to the second wheel falls within the target slip ratio range.

4. The method according to claim 1, characterized in that, Controlling the vehicle to enter anti-lock braking state includes: The motor braking system corresponding to each wheel of the vehicle brakes the vehicle based on the corresponding preset braking parameters.

5. The method according to claim 4, characterized in that, The preset braking parameters are associated with the road surface condition of the road on which the vehicle travels; the road surface condition includes a uniform road surface; when the vehicle is traveling on the uniform road surface, the difference between the road surface adhesion coefficients corresponding to each wheel of the vehicle is less than the difference threshold. The preset braking parameters associated with the uniform road surface instruct the motor braking system of each wheel of the vehicle to brake the vehicle with the same motor braking parameters.

6. The method according to claim 4, characterized in that, The preset braking parameters are associated with the road surface conditions on which the vehicle travels; the road surface conditions include split-road surfaces; when the vehicle is traveling on the split-road surfaces, the road surface adhesion coefficient corresponding to the wheel on one side of the vehicle is greater than the road surface adhesion coefficient corresponding to the wheel on the other side of the vehicle. The preset braking parameters associated with the split road surface indicate that the motor braking parameters of the motor braking system of the wheel located on one side of the vehicle are greater than the motor braking parameters of the motor braking system of the wheel located on the other side of the vehicle.

7. The method according to claim 4, characterized in that, The preset braking parameters are associated with the road surface condition of the road on which the vehicle travels; the road surface condition includes the connecting road surface; when the vehicle is traveling on the connecting road surface, the road surface adhesion coefficient corresponding to at least one wheel of the vehicle changes from a first adhesion coefficient to a second adhesion coefficient. The preset braking parameters associated with the docking road surface include at least two preset braking parameters, which are the same number as at least two adhesion coefficients.

8. The method according to claim 1, characterized in that, The method further includes: Obtain the status information of the motor braking system; the status information includes at least one of the following: available braking torque of the motor, speed controller status, and battery charging power limit. Based on the status information, the maximum available braking parameters of the motor braking system are determined; Based on the mapping relationship between braking condition data and braking parameters, the target braking parameters corresponding to the braking condition data are determined. If the maximum available braking parameter is greater than or equal to the target braking parameter, the target braking parameter is determined as the motor braking parameter when the motor braking system brakes the vehicle. Alternatively, if the maximum available braking parameter is less than the target braking parameter, the maximum available braking parameter may be determined as the motor braking parameter.

9. The method according to claim 8, characterized in that, The electric braking system includes a motor and a battery; the vehicle includes a suspension system; the mapping relationship between the braking condition data and braking parameters is obtained based on the maximum reverse torque capability curve of the motor, the maximum continuous charging power of the battery, and the maximum tolerable torque impact of the suspension system under each braking condition parameter.

10. The method according to claim 8, characterized in that, After controlling the vehicle to enter the anti-lock braking state, the method further includes: Update the status information of the motor braking system; Based on the updated status information, the updated maximum available braking parameters of the motor braking system are determined; If the updated maximum available braking parameter is less than the motor braking parameter, the updated maximum available braking parameter shall be determined as the updated motor braking parameter; The electric motor braking system is controlled to brake the vehicle based on the updated electric motor braking parameters.

11. The method according to claim 10, characterized in that, After controlling the electric motor braking system to brake the vehicle based on the updated electric motor braking parameters, the method further includes: Based on the difference between the updated motor braking parameters and the original motor braking parameters, the hydraulic braking parameters are increased accordingly, so that the sum of the increased hydraulic braking parameters and the updated motor braking parameters matches the target braking parameters indicated by the anti-lock braking signal.

12. The method according to any one of claims 1 to 11, characterized in that, Before controlling the vehicle to enter the anti-lock braking state in response to a triggered anti-lock braking signal, the method further includes: Upon receiving a braking operation, determine the target deceleration and the target deceleration rate indicated by the braking operation; The anti-lock braking signal is triggered when the target deceleration is greater than the deceleration threshold and the rate of change of the target deceleration is greater than the rate of change threshold.

13. The method according to claim 12, characterized in that, After controlling the vehicle to enter the anti-lock braking state, the method further includes: If, during the first duration, the target deceleration remains less than or equal to the deceleration threshold, or if the vehicle's speed is less than the speed threshold, the vehicle is controlled to exit the anti-lock braking state. During the second duration, the motor braking parameters are gradually reduced to 0, and the hydraulic braking parameters are gradually increased to the total braking parameters indicated by the braking operation.

14. An anti-lock braking control device for a vehicle, characterized in that, The vehicle includes an electric braking system and a hydraulic braking system; the anti-lock braking control device includes: The control module is used to control the vehicle to enter the anti-lock braking state in response to the triggered anti-lock braking signal; in the anti-lock braking state, the electric braking system and the hydraulic braking system jointly brake the vehicle; The acquisition module is used to acquire the braking condition data of the vehicle. The adjustment module is used to adjust the hydraulic braking parameters of the hydraulic braking system only when braking the vehicle, based on the braking condition data.

15. An electronic device, characterized in that, include: Memory, processor, and computer programs; The computer program is stored in the memory and configured to be executed by the processor to implement the method as described in any one of claims 1-13.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-13.

17. A vehicle, characterized in that, include: The electronic device as claimed in claim 15; and / or The computer-readable storage medium as claimed in claim 16.

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