Control method of a braking system and vehicle

Abstract

The present disclosure relates to the technical field of brake control, in particular to a control method of a brake system and a vehicle. The present disclosure determines the target brake demand of each wheel first, then determines the corresponding brake control strategy for each wheel independently according to the state parameters of each wheel, and controls the motor brake system and / or the hydraulic brake system to brake accordingly, so as to realize the independent and fine distribution and control of the motor brake force and the hydraulic brake force of each wheel, take into account the actual state differences of each wheel, and improve the brake safety and energy recovery efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of braking control technology, and in particular to a control method for a braking system and a vehicle. Background Technology

[0002] In new energy vehicles, the braking system is usually equipped with both an electric motor braking system and a hydraulic braking system. During braking, the electric motor braking system can convert the vehicle's kinetic energy into electrical energy for recovery and storage, while the hydraulic braking system consumes the vehicle's kinetic energy through friction.

[0003] Currently, a typical braking force distribution scheme is to uniformly set the ratio of electric motor braking and hydraulic braking for the whole vehicle, and control the output of the electric motor braking system and hydraulic braking system according to a fixed ratio.

[0004] However, in actual driving, a fixed electro-hydraulic distribution ratio is difficult to adapt to complex driving conditions, resulting in insufficient braking safety and energy recovery efficiency. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure provides a control method for a braking system and a vehicle.

[0006] A first aspect of this disclosure provides a control method for a braking system, comprising: Based on the vehicle's braking information during braking, the target braking force corresponding to each wheel is determined; The braking control strategy corresponding to the target wheel is determined based on the state parameters of the target wheel and / or the braking system parameters. The braking control strategy is used to make the braking force of the target wheel reach the target braking force. According to the braking control strategy, the braking torque output by the vehicle's electric braking system and / or hydraulic braking system to the target wheels is controlled.

[0007] A second aspect of this disclosure provides a vehicle including electronic devices, the electronic devices comprising: processor; Memory, used to store executable instructions; The processor is configured to read the executable instructions from the memory and execute the executable instructions to implement the method of the first aspect described above.

[0008] The technical solution provided in this disclosure has the following advantages compared with the prior art: The braking system control method and vehicle provided in this disclosure first determine the target braking demand of each wheel, then independently determine the corresponding braking control strategy for each wheel based on its state parameters, and control the electric motor braking system and / or hydraulic braking system accordingly to perform braking. This achieves independent and refined allocation and control of the electric motor power and hydraulic braking force of each wheel, which can take into account the actual state differences of each wheel and improve braking safety and energy recovery efficiency. Attached Figure Description

[0009] 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.

[0010] 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.

[0011] Figure 1 This is a flowchart of a control method for a braking system provided in an embodiment of this disclosure; Figure 2 This is a flowchart of a control method for a braking system provided in another embodiment of this disclosure; Figure 3 This is a flowchart of a control method for a braking system provided in another embodiment of this disclosure; Figure 4 This is a schematic diagram of a four-level progressive four-wheel braking force distribution strategy provided in an embodiment of this disclosure; Figure 5 This is a diagram of the target wheel closed-loop control architecture provided in an embodiment of this disclosure; Figure 6 This is a schematic diagram of the structure of a control device for a braking system provided in an embodiment of this disclosure; Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this disclosure. Detailed Implementation

[0012] 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.

[0013] 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.

[0014] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.

[0015] 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.

[0016] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0017] Typically, the braking system of new energy vehicles includes both an electric motor braking system and a hydraulic braking system. The electric motor braking system converts the vehicle's kinetic energy into electrical energy through a drive motor, achieving energy recovery. The hydraulic braking system, on the other hand, converts kinetic energy into heat energy through the friction between the brake pads and the brake disc. Existing braking force distribution schemes usually set a fixed electro-hydraulic distribution ratio at the vehicle level and uniformly control all four wheels according to this fixed ratio. However, in actual driving, vehicles encounter various complex conditions such as uphill and downhill slopes, split-road surfaces (i.e., surfaces where the left and right wheels have different coefficients of friction), manhole covers, and speed bumps. Under these conditions, the vertical load on each wheel and the road surface adhesion conditions change in real time. A fixed distribution ratio cannot adapt to these dynamic changes, leading to low energy recovery efficiency in some conditions, and even wheel lock-up or skidding due to improper braking force distribution in emergency or special road conditions, endangering driving safety.

[0018] To address this problem, this disclosure provides a control method for a braking system, which will be described below with reference to specific embodiments.

[0019] Figure 1 This is a flowchart illustrating a control method for a braking system according to an embodiment of this disclosure. This method can be executed by a control device for the braking system, which can be implemented in software and / or hardware. The control device can be configured in an electronic device, such as an in-vehicle device, a vehicle's on-board controller, or a brake controller. It is understood that the control method for the braking system provided in this disclosure can also be applied to other vehicles with similar requirements for brake energy recovery and hydraulic brake force distribution.

[0020] The following is about Figure 1 The control method of the braking system shown will be introduced. For example... Figure 1 As shown, the control method of the braking system provided in this embodiment includes the following steps.

[0021] S110. Based on the vehicle's braking information during braking, determine the target braking force corresponding to each wheel.

[0022] Braking information refers to a set of parameters that reflect the driver's braking intention and the vehicle's current driving status. For example, braking information may include brake pedal opening, brake pedal depressor rate, current vehicle speed, and vehicle mass.

[0023] The brake pedal opening is used to quantify the depth at which the driver depresses the brake pedal; this value is directly acquired by a displacement sensor or angle sensor located at the brake pedal. The brake pedal depressing rate reflects the speed at which the driver depresses the pedal; it can be obtained by time differentiation of the pedal opening signal and is used to distinguish between regular braking and emergency braking. Current vehicle speed can be obtained through wheel speed sensors or the onboard GPS module. Vehicle mass can be estimated in real time using a vehicle dynamics model, or directly obtained by adding the vehicle's curb weight to the passenger and cargo mass measured by load sensors.

[0024] In addition, braking information can also include information such as the vehicle's longitudinal acceleration and slope angle. This information can be obtained through sensors such as inertial measurement units (IMUs) to more accurately assess the axle load transfer of the vehicle on the slope.

[0025] In this step, the target braking force for each wheel is determined based on the aforementioned braking information. This involves converting the driver's braking demand into a specific braking torque value that each wheel needs to generate. This process requires comprehensive consideration of various factors, including the overall braking demand of the vehicle, the load distribution between the front and rear axles, and the adhesion conditions of the left and right wheels.

[0026] Electronic devices acquire multi-dimensional braking information and calculate the target braking force for each wheel independently based on this information, providing a reliable foundation for electro-hydraulic distribution.

[0027] S120. Determine the braking control strategy corresponding to the target wheel based on the state parameters of the target wheel and / or the braking system parameters.

[0028] Among them, the braking control strategy is used to make the braking force of the target wheel reach the target braking force.

[0029] In this embodiment of the disclosure, the target wheel refers to any one of the four wheels of the vehicle. After the target braking force for each wheel has been determined in step S110, this step requires determining the specific braking control strategy that should be followed when the braking force is applied to each target wheel.

[0030] It should be noted that although each wheel eventually needs to reach its corresponding target braking force, the specific control strategy for each wheel to reach that target braking force is different because the real-time state of each wheel, the road environment, and the vehicle's own system state may vary.

[0031] For example, if one wheel is on a dry road surface with a high coefficient of friction and its motor has sufficient regenerative braking force, then its control strategy can be to primarily use motor braking; while the other wheel is on an icy or snowy road surface with a low coefficient of friction, its control strategy should be to limit the total braking force to prevent lock-up.

[0032] Therefore, it is necessary to obtain the state parameters of the target wheel and / or braking system parameters as a basis for determining its specific control strategy. The state parameters of the target wheel refer to physical quantities reflecting the current motion state of the wheel and the characteristics of its environment. For example, state parameters may include the wheel's longitudinal slip ratio, the road surface adhesion coefficient corresponding to the wheel, road surface characteristics (whether there are potholes or obstacles) in the wheel's direction of travel, and the wheel's vertical load, etc.

[0033] Braking system parameters refer to parameters that reflect the operating status of the vehicle's braking system itself or the driver's operating characteristics. For example, braking system parameters may include the temperature of the drive motor, the state of charge of the vehicle's power battery, and the rate at which the brake pedal is depressed. These parameters affect the availability of the electric braking system or trigger specific braking modes.

[0034] Based on the aforementioned state parameters and / or braking system parameters, the electronic equipment will match the most suitable braking control strategy for the target wheel, with the goal of making the braking force of the wheel reach the target braking force. However, the constraints and execution methods will vary depending on the specific operating conditions.

[0035] S130. According to the braking control strategy, control the braking torque output by the vehicle's electric braking system and / or hydraulic braking system to the target wheel.

[0036] An electric motor braking system is a system that uses the reverse torque generated by the vehicle's drive motor during braking to apply braking force to the wheels. When the drive motor operates in regenerative braking mode, its output reverse torque is the motor's driving torque. The electric motor braking system can convert the vehicle's kinetic energy into electrical energy and store it in the power battery, thereby achieving energy recovery.

[0037] A hydraulic braking system is a system that uses brake fluid as a transmission medium to generate frictional braking force by pushing brake pads to clamp the brake disc through components such as the master cylinder, brake lines, and wheel cylinders.

[0038] The electronic equipment translates the braking control strategy of the target wheel into specific execution commands, which are then sent to the motor controller of the electric braking system and the hydraulic actuator of the hydraulic braking system, respectively, to control them to output corresponding torques to the target wheel.

[0039] Ultimately, the braking force of the target wheel is the result of the combined action of the electric braking torque and the hydraulic braking torque.

[0040] Understandably, the electronic devices are capable of performing the above steps independently for each wheel.

[0041] This embodiment of the invention first determines the target braking demand of each wheel, then independently determines the corresponding braking control strategy for each wheel based on its state parameters, and controls the motor braking system and / or hydraulic braking system accordingly to perform braking. This achieves independent and precise allocation and control of the electric motor power and hydraulic braking force of each wheel, taking into account the actual state differences of each wheel, and improving braking safety and energy recovery efficiency.

[0042] The process of determining the target braking force of the wheel is explained below.

[0043] In some embodiments, determining the target braking force corresponding to each wheel based on the vehicle's braking information during braking includes: determining the vehicle's total braking torque based on the vehicle's braking information during braking; and determining the target braking force corresponding to each wheel based on the total braking torque. The sum of the target braking forces corresponding to each wheel is the braking force corresponding to the total braking torque.

[0044] Braking information includes brake pedal opening. Brake pedal depressing rate Speed Vehicle quality .

[0045] Through vehicle dynamics model The process of calculating the total braking torque can be expressed as:

[0046] Among them, brake pedal opening The rate at which the brake pedal is depressed, used to reflect the driver's braking intention. This system is used to distinguish between emergency braking and normal braking. When the brake pedal depressing rate exceeds a preset threshold, it is determined to be an emergency braking condition, and braking safety must be prioritized. When the depressing rate does not exceed the preset threshold, it is determined to be a normal braking condition, and energy recovery efficiency must be prioritized.

[0047] Furthermore, the total braking torque is distributed to each wheel of the vehicle to obtain the target braking torque corresponding to each wheel, thereby determining the target braking force. For example, the total braking torque is distributed to each wheel of the vehicle according to a certain ratio.

[0048] In some embodiments, the target braking force corresponding to each wheel is determined based on the total braking torque. First, the braking torque corresponding to each axle is determined based on the vertical load of each axle of the vehicle and a first correction coefficient. The sum of the braking torques corresponding to each axle is used to make the vehicle's braking force reach the braking force corresponding to the total braking torque.

[0049] Vertical load refers to the actual load borne by the front axle and the rear axle respectively under braking dynamics.

[0050] The function of the first correction factor is to make fine adjustments based on the ideal braking force distribution curve (such as the I curve) according to parameters such as wheelbase and center of gravity of the specific vehicle model, so that the distribution ratio of each axle to the total braking torque is within the preset safe range, and the braking force ratio of the front and rear axles is close to the ideal distribution ratio, so as to prevent any axle from locking up first.

[0051] Specifically, based on the real-time axle load transfer calculation results, the total braking torque is distributed to the front and rear axles. Axle load transfer amount It is determined by the vehicle's longitudinal acceleration and slope angle.

[0052] When braking uphill, the axle load is transferred from the front axle to the rear axle, and when braking downhill, the axle load is transferred from the rear axle to the front axle.

[0053] Correspondingly, when the vehicle brakes on an uphill section, the axle load shifts to the rear axle due to the gradient, increasing the vertical load on the rear axle and decreasing the vertical load on the front axle. At this time, based on the real-time axle load transfer and braking force distribution curve, the regenerative braking force of the rear-wheel drive motor is prioritized to fully utilize its energy recovery capability. The hydraulic braking force is dynamically adjusted to supplement the actual output of the electric motor, ensuring that the total braking torque meets the driver's needs while maintaining braking stability. When the vehicle brakes on a downhill section, the axle load shifts to the front axle, increasing the vertical load on the front axle.

[0054] The intelligent electro-hydraulic braking calculation model prioritizes increasing the regenerative braking force of the front-wheel drive motor to fully utilize its energy recovery capability. Simultaneously, considering the potentially prolonged downhill braking duration, motor overheat protection must be considered, smoothly transitioning to hydraulic braking when the motor temperature approaches a threshold.

[0055] Axle load transfer Represented as:

[0056] in, For vehicle quality, For longitudinal acceleration, The height of the vehicle's center of gravity from the ground. This refers to the wheelbase.

[0057] The increase in rear axle load when going uphill is:

[0058] The increase in front axle load when going downhill is:

[0059] in The slope angle, This is the acceleration due to gravity.

[0060] Front axle braking torque for:

[0061] Rear axle braking torque for:

[0062] in The front axle load is determined based on the front axle vertical load and the increase in front axle load. The load is the rear axle load, determined based on the rear axle vertical load and the increase in rear axle load. , This is the first correction factor for the front and rear axles, which is dynamically adjusted according to the type of working conditions.

[0063] After determining the braking torque for each axle, the braking torque for each axle is distributed to the multiple wheels corresponding to that axle, resulting in a target braking torque for each wheel. This target braking torque is used to provide the target braking force to the target wheel. For example, for each axle, the braking torque is distributed to the left and right wheels corresponding to that axle according to a certain ratio.

[0064] Specifically, each axle corresponds to multiple wheels, typically the left and right wheels. For each axle, the braking torque corresponding to the axle is allocated based on the road adhesion coefficient corresponding to the two wheels on each side of the axle and a second correction coefficient, thus obtaining the target braking torque corresponding to each wheel on each side.

[0065] The second correction coefficient is used to control the yaw moment generated by the difference in braking force between the two wheels on the same axle to be less than a preset safety threshold.

[0066] On a flat road surface and under straight braking conditions, the braking torque of the tires on both sides of the same axle is distributed equally to the axle, meaning that the target braking torque of each wheel is the same.

[0067] Under conditions such as split-wheel surfaces, the coefficients of friction for the wheels on the left and right sides of the same axle differ. Theoretically, the side with higher friction can receive more braking force, while the side with lower friction receives less. However, the difference in braking force between the two sides creates a yaw moment that causes the vehicle to rotate around its vertical axis. If this yaw moment is too large, the driver will find it difficult to correct it with the steering wheel, and the vehicle will lose directional stability. Therefore, the second correction coefficient dynamically limits the difference in braking force between the left and right wheels based on the current vehicle speed and steering wheel angle, ensuring that the resulting yaw moment is always less than a safe threshold that can be easily compensated for by the driver. This allows the vehicle to recover energy using the difference in wheel friction while maintaining its path-tracking capability.

[0068] Yaw moment generated by the difference in braking force between the left and right wheels The constraints are expressed as follows:

[0069] in Due to the difference in braking force between the left and right wheels, The wheelbase is the distance between the wheels. This is a preset safety threshold.

[0070] Taking a four-wheeled vehicle as an example, the target braking torque allocated to each wheel is:

[0071]

[0072]

[0073]

[0074] in, , , , The target braking torques are, in order, the front left, front right, rear left, and rear right wheels. , , , The coefficients of friction for the front left, front right, rear left, and rear right wheels are shown in order. , , , The second correction coefficients for the left front, right front, left rear, and right rear wheels are respectively 0.5 for symmetrical road surfaces.

[0075] Based on the above allocation method, the target braking torque of each wheel can be determined, and the braking force that the target braking torque can provide to the wheel is the target braking force corresponding to each wheel.

[0076] This embodiment of the invention provides a reasonable calculation method for determining the target braking force of each wheel by utilizing the progressive distribution of the vehicle's total braking torque, the braking torque of the axles, and the target braking torque of each wheel. It introduces physical constraints such as axle load transfer and yaw moment limitation, so that the braking force finally distributed to each wheel not only meets the driver's overall deceleration needs but also meets the requirements of vehicle dynamic stability, providing a reasonable and safe basis for subsequent electro-hydraulic distribution.

[0077] Once the target braking torque for each wheel is determined, the distribution of regenerative braking force from the electric motor and hydraulic braking force can be performed. The general principle of this process is to prioritize electric motor braking and supplement it with hydraulic braking.

[0078] Specifically, for each wheel, the maximum available regenerative braking torque of the motor corresponding to the wheel is queried. This value is limited by factors such as motor speed, temperature, and remaining battery charge percentage (State of Charge, SOC).

[0079] If the target braking torque corresponding to the wheel is less than or equal to the maximum available regenerative braking torque of the motor, then the braking is entirely provided by the motor braking system, and the hydraulic braking system does not intervene.

[0080] If the target braking torque corresponding to the wheel is greater than the maximum available regenerative braking torque of the motor, the motor braking system provides the maximum available regenerative braking force, and the remaining part is supplemented by the hydraulic braking system.

[0081] Under special working conditions, the control ratio of the motor control system and hydraulic braking system of a specific wheel is adjusted to keep the braking force corresponding to the target braking torque constant.

[0082] The different braking control strategies are explained below.

[0083] In some embodiments, a first control strategy is employed in the normal braking mode.

[0084] Specifically, the state parameters include longitudinal slip ratio and road surface adhesion coefficient. Based on the state parameters of the target wheel, the braking control strategy corresponding to the target wheel is determined, including: when the absolute value of the longitudinal slip ratio of the target wheel is less than the lower limit of the preset slip ratio range and the road surface adhesion coefficient corresponding to the target wheel is greater than the upper limit of the preset coefficient range, the braking control strategy corresponding to the target wheel is determined as the first control strategy.

[0085] A preset slip ratio range is used to determine whether the wheel slip ratio is within the ideal range. For example, when the slip ratio is set to be maintained between 0.08 and 0.12, the wheel can obtain the maximum longitudinal adhesion coefficient, resulting in the highest braking efficiency and minimizing wheel lock-up. Therefore, the preset slip ratio range can be set as an interval centered on this ideal range. For example, the lower limit of the preset slip ratio range is 0.05. When the absolute value of the longitudinal slip ratio of the target wheel is less than the lower limit of the preset slip ratio range, it indicates that the target wheel is in a state of pure rolling or near-pure rolling, with sufficient braking redundancy.

[0086] Longitudinal slip ratio The calculation method is as follows:

[0087] in Here is the linear velocity of the wheel, and here is the rotational speed of the wheel. With rolling radius The product of these can be expressed as:

[0088] Wheel speed can be directly measured by wheel speed sensors.

[0089] The preset coefficient range is a parameter range used to judge the road surface adhesion conditions. When the road surface adhesion coefficient corresponding to the target wheel is greater than the upper limit of the preset coefficient range (e.g., 0.3), it indicates that the road surface condition is good (e.g., dry or wet asphalt road surface), and the wheel can provide greater braking force without easily locking up.

[0090] When both of the above conditions are met simultaneously, it indicates that the target wheel is in a stable operating condition with high adhesion and no risk of wheel lock-up. At this point, the first control strategy is adopted. The main purpose of the first control strategy is to maximize the energy recovery capability of the electric motor braking system while ensuring braking stability.

[0091] Accordingly, according to the braking control strategy, the vehicle's electric braking system and / or hydraulic braking system are controlled to brake the target wheel, including: when the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the first target torque, controlling the electric braking system to output the first target torque to the target wheel; when the maximum available regenerative braking torque corresponding to the target wheel is less than the first target torque, controlling the electric braking system to output the maximum available regenerative braking torque to the target wheel and controlling the hydraulic braking system to output the first compensation torque to the target wheel.

[0092] The first target torque is used to make the braking force of the target wheel reach the target braking force. The sum of the maximum available regenerative braking torque and the first compensation torque is used to make the braking force of the target wheel reach the target braking force.

[0093] The maximum available regenerative braking torque refers to the maximum reverse torque that the motor braking system can output under the current conditions. This value is subject to various factors, such as the peak value of the external characteristics at the current motor speed, the temperature limit of the motor windings, and the allowable charging power of the power battery. The first target torque is the torque corresponding to the target braking force calculated for the target wheel in step S110, and the first compensation torque is the difference between the first target torque and the actual output torque of the motor.

[0094] Under the first control strategy, the electric motor braking system is used preferentially. The electronic system first determines whether the motor's capacity is sufficient to meet the braking requirements of the target wheel. If so, the motor provides braking entirely, without intervention from the hydraulic system, thus achieving full energy recovery. If the motor's capacity is insufficient, it is controlled to operate at maximum capacity, with the remaining insufficient braking force supplemented by the hydraulic braking system.

[0095] This embodiment controls the triggering conditions of the first control strategy based on the longitudinal slip ratio of the wheel and the road surface adhesion coefficient, ensuring that motor braking is used preferentially only when braking stability is sufficient, thereby maximizing energy recovery efficiency under the premise of safety and controllability.

[0096] In some embodiments, a second control strategy is employed when the road surface adhesion coefficient is low and there is a risk of wheel lock-up.

[0097] Specifically, the state parameters include longitudinal slip ratio and road surface adhesion coefficient. Based on the state parameters of the target wheel, the braking control strategy corresponding to the target wheel is determined, including: when the absolute value of the longitudinal slip ratio of the target wheel is greater than the upper limit of the preset slip ratio range and the road surface adhesion coefficient corresponding to the target wheel is less than the lower limit of the preset coefficient range, the braking control strategy corresponding to the target wheel is determined to be the second control strategy.

[0098] The upper limit of the preset slip ratio range can be set to, for example, 0.15. When the absolute value of the longitudinal slip ratio of the target wheel exceeds this upper limit, it indicates that the target wheel has entered an unstable state, the slip ratio is too large, the lateral adhesion between the tire and the road surface decreases sharply, and the wheel is about to lock up or has already locked up.

[0099] The lower limit of the preset coefficient range can be set, for example, to 0.2. When the road surface adhesion coefficient is less than this lower limit, it indicates that the road surface is very smooth (such as an icy or snowy road surface), and the adhesion between the wheels and the road surface is limited.

[0100] When both of the above conditions are met simultaneously, it indicates that the target wheel is currently in a dangerous condition of low adhesion and high slip ratio. In this situation, maintaining the original target braking force may lead to wheel lock-up and loss of vehicle control. Therefore, a second control strategy is adopted. The main purpose of the second control strategy is to prioritize ensuring braking stability and prevent wheel lock-up.

[0101] Accordingly, according to the braking control strategy, the vehicle's electric braking system and / or hydraulic braking system are controlled to brake the target wheels, including: reducing the target braking force; controlling the hydraulic braking system to reduce the braking torque output to the target wheels; and controlling the electric braking system to increase the braking torque output to the target wheels.

[0102] Among them, the sum of the braking torque output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force, and to reduce the longitudinal slip ratio of the target wheel to a preset coefficient range.

[0103] Optionally, lowering the target braking force refers to determining the maximum braking force that the wheel can safely withstand based on the current road surface adhesion coefficient and vertical load, and using this maximum braking force as the lowered target braking force. For example, the degree of reduction is positively correlated with the smoothness of the road surface.

[0104] After determining the target braking force after reduction, the outputs of the electric braking system and the hydraulic braking system are adjusted. The braking torque output of the hydraulic braking system, which is prone to locking, is reduced. At the same time, the braking torque output of the electric braking system is dynamically adjusted to compensate for the reduced braking force of the hydraulic braking system. Through the cooperation of the two, the slip ratio of the target wheel is restored to a safe preset coefficient range.

[0105] Optionally, sliding mode control or model predictive control can be used for the control algorithms of the electric braking system and the hydraulic braking system to ensure rapid response in a short time.

[0106] This embodiment of the invention achieves active protection of braking safety by promptly reducing the target braking force when a low risk of brake lock-up is detected, and by reducing the output torque of the hydraulic braking system and increasing the output torque of the electric motor braking system based on the reduced target braking force. Under the premise of ensuring vehicle control stability, it can still provide a certain braking force and recover some energy, thus balancing safety and efficiency.

[0107] In some embodiments, a third control strategy is adopted when there are road conditions such as manhole covers in the direction of travel of the target wheels.

[0108] Specifically, the state parameters include vertical load. Based on the state parameters of the target wheel, the braking control strategy corresponding to the target wheel is determined, including: when there are potholes on the road surface in the direction of travel of the target wheel that reduce the vertical load of the target wheel and the rate of change is greater than the first load change rate threshold, the braking control strategy corresponding to the target wheel is determined to be the third control strategy.

[0109] In this embodiment, the presence of potholes on the road surface can be predicted in advance using a vehicle big data model based on positioning and high-precision map data, or it can be identified in real time using sensors such as onboard forward-facing cameras or radar. When a wheel passes over a pothole, the vertical load on the wheel suddenly decreases due to the drop in suspension, causing the wheel to instantly lose a significant amount of traction.

[0110] The first load change rate threshold is used to determine the severity of the load reduction. At the instant the wheel passes over a pothole, the vertical load drops sharply, and the upper limit of braking force it can withstand also decreases drastically. If the original braking force is maintained at this time, the wheel is very likely to lock up. Therefore, a third control strategy is adopted. The main purpose of the third control strategy is to smoothly reduce the braking force, preventing sudden changes in braking force due to load abrupt changes, thereby ensuring the vehicle's ride comfort and stability.

[0111] Accordingly, according to the braking control strategy, the vehicle's electric braking system and / or hydraulic braking system are controlled to brake the target wheel, including: reducing the target braking force; controlling the rate of change of the output torque of the hydraulic braking system to the target wheel to be reduced to below a preset rate of change threshold; and controlling the electric braking system to adjust the braking torque output to the target wheel.

[0112] Among them, the sum of the braking torque output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force.

[0113] The purpose of lowering the target braking force is similar to that of the second control strategy: to redetermine the safe target braking force based on the reduced vertical load.

[0114] Due to the mechanical characteristics of hydraulic braking systems, rapid changes in torque can produce a noticeable impact. Therefore, it is necessary to control the rate of change of the output torque of the hydraulic braking system and limit it to a safe preset threshold (e.g., 500 kPa / s) to avoid instantaneous impact on the target wheel and thus achieve a smooth transition.

[0115] While the hydraulic braking force changes smoothly, the electric motor braking system needs to adjust its output torque accordingly. When the rate of change of the hydraulic braking force is limited, the rapid response of the electric motor braking system can compensate for or absorb the difference in braking force, ensuring that the total braking force provided by the electric motor braking system and the hydraulic control system to the target wheel reaches the target braking force when the target wheel passes through the pothole.

[0116] This embodiment of the invention effectively avoids sudden changes in braking force and vehicle instability caused by abrupt road surface changes by identifying pothole conditions and proactively reducing the target braking force and limiting the rate of hydraulic pressure change, thereby improving vehicle ride smoothness and comfort. Simultaneously, the compensation of braking torque by the electric motor braking system ensures stable braking force, balancing smoothness and braking performance.

[0117] In some embodiments, a fourth control strategy is employed when there is a protruding obstacle in front of the wheels.

[0118] Specifically, the state parameters include vertical load. Based on the state parameters of the target wheel, the braking control strategy corresponding to the target wheel is determined, including: when there is an obstacle on the road surface in the direction of travel of the target wheel that increases the vertical load of the target wheel and the rate of change is greater than the second load change rate threshold, the braking control strategy corresponding to the target wheel is determined to be the fourth control strategy.

[0119] When a wheel travels over a speed bump or other protruding obstacle, the suspension is compressed sharply, and the vertical load on the wheel increases suddenly. The second load change rate threshold is used to determine the severity of the load increase.

[0120] When a rotating wheel impacts an obstacle, excessive braking force can cause enormous impact loads on the transmission system and suspension components, potentially leading to wheel lock-up or severe pitching vibrations. Therefore, a fourth control strategy is employed. The primary objective of this strategy is to reduce the target braking force on the target wheel, preventing it from locking up due to the impact of the speed bump, while simultaneously compensating using the braking forces of other wheels and regenerative braking from the motor.

[0121] Accordingly, according to the braking control strategy, the vehicle's electric braking system and / or hydraulic braking system are controlled to brake the target wheel, including: reducing the target braking force; when the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the second target torque, controlling the electric braking system to output the second target torque to the target wheel; when the maximum available regenerative braking torque corresponding to the target wheel is less than the second target torque, controlling the electric braking system to output the maximum available regenerative braking torque to the target wheel and controlling the hydraulic braking system to output the second compensation torque to the target wheel.

[0122] The second target torque is used to bring the braking force of the target wheel to the reduced target braking force. The sum of the maximum available regenerative braking torque and the second compensation torque is used to bring the braking force of the target wheel to the reduced target braking force.

[0123] The fourth control strategy is similar in logic to the first control strategy, but unlike the first control strategy, before passing over the speed bump, the electronic device will reduce the target braking force and then prioritize the use of the maximum available regenerative braking torque of the electric motor braking system to provide the reduced target braking force to the target wheel. When the maximum available regenerative braking torque is insufficient, the hydraulic braking system will output a second target torque to make up for it.

[0124] Optionally, when the target wheel passes over an obstacle, the reduced target braking force is restored to the target braking force according to a preset recovery rate.

[0125] After the target wheel's tires pass over the speed bump, the vertical load returns to normal, and the electronic system gradually restores the previously reduced target braking force to the original target braking force that matches the driver's intention. A preset recovery rate controls the rate of change of the target braking force, ensuring a smooth recovery.

[0126] This embodiment of the invention reduces the target braking force when encountering road bumps or obstacles, thus preventing wheel lock-up caused by the impact of speed bumps on the target wheels, and smoothly returns to normal operating conditions after passing the obstacle, further improving the accuracy of braking control.

[0127] In some embodiments, a fifth control strategy is employed when the motor is overheated or the vehicle is fully charged.

[0128] Specifically, the braking system parameters include the temperature of the motor and / or the battery level of the vehicle. Based on the braking system parameters, the braking control strategy corresponding to the target wheel is determined, including: when the temperature of the vehicle's motor is greater than a preset temperature threshold, or when the vehicle's battery level reaches its maximum, the braking control strategy corresponding to the target wheel is determined to be the fifth control strategy.

[0129] The preset temperature threshold is a safe upper limit set by the motor controller to protect the motor, such as 150℃. When the vehicle's battery reaches its maximum charge level, i.e., the state of charge (SOC) of the power battery is 100%, the battery can no longer accept any charging current. In any of the above situations, the motor braking system cannot or should not continue to operate, otherwise it will lead to motor damage or battery overcharging.

[0130] Accordingly, according to the braking control strategy, the vehicle's electric braking system and / or hydraulic braking system are controlled to brake the target wheel, including: controlling the electric braking system to reduce the braking torque output to the target wheel to zero, and the duration of the electric braking system reducing the braking torque output to the target wheel is greater than a preset time threshold; and controlling the hydraulic braking system to output a third compensation torque to the target wheel.

[0131] The sum of the braking torque output by the electric motor braking system to the target wheel and the third compensation torque is used to make the braking force of the target wheel reach the target braking force.

[0132] When the fifth control strategy is adopted, the regenerative braking torque of the motor needs to be gradually reduced to zero. To ensure vehicle stability and driving experience, this withdrawal process must avoid sudden torque changes. Therefore, a preset time threshold is set to prevent sudden changes in vehicle deceleration caused by the sudden disappearance of torque. As the motor torque gradually withdraws, the hydraulic braking system simultaneously increases its output torque, providing an additional third compensating torque.

[0133] Ultimately, when the output torque of the electric motor braking system drops to zero, all the target braking force is provided by the hydraulic braking system.

[0134] Furthermore, the electronic equipment monitors the motor status in real time and smoothly resumes regenerative braking of the motor when conditions permit.

[0135] This embodiment of the invention takes into account the physical limits of the braking system and sets up two protection mechanisms: motor overheating and battery full charge. It also sets up a smooth disengagement mechanism for the motor braking system, which is compensated in a timely manner by the hydraulic braking system. This not only protects the safety of key components but also ensures the continuity of braking function and the user's driving experience under this operating condition.

[0136] In some embodiments, a sixth control strategy is employed when the driver applies emergency braking.

[0137] Specifically, the braking system parameters include the braking pedal depressing rate. Based on the braking system parameters, the braking control strategy corresponding to the target wheel is determined, including: when the braking pedal depressing rate is greater than a preset rate threshold, the braking control strategy corresponding to the target wheel is determined to be the sixth control strategy.

[0138] The preset rate threshold is a critical rate value used to distinguish between normal braking and emergency braking. When the pedaling rate exceeds the preset rate threshold, it indicates that the driver has initiated an emergency braking operation, representing the driver's intention to shorten the braking distance as much as possible. At this time, energy recovery of the vehicle is abandoned, and priority is given to meeting the driver's intention.

[0139] Accordingly, controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel includes: controlling the hydraulic braking system to output a third target torque to the target wheel when the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is greater than or equal to the third target torque; and controlling the electric braking system to output a fourth compensating torque to the target wheel when the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is less than the third target torque.

[0140] The third target torque is used to ensure that the braking force of the target wheel reaches the target braking force. The sum of the maximum hydraulic braking torque and the fourth compensation torque is used to ensure that the braking force of the target wheel reaches the target braking force.

[0141] Under the sixth control strategy, since the hydraulic braking system can provide the maximum braking force, the electronic device first determines whether the hydraulic braking system has sufficient capacity to bear the target braking force of the target wheel alone. If the maximum hydraulic braking torque is greater than or equal to the third target torque, then the hydraulic braking system provides the full braking force of the target wheel.

[0142] If the maximum hydraulic braking torque is less than the third target torque, the maximum capacity of the hydraulic braking system is insufficient to meet the needs of emergency braking. In this case, the control motor braking system outputs the remaining fourth compensation torque to ensure that the braking distance is shortened to the greatest extent.

[0143] Meanwhile, the Anti-lock Braking System (ABS) independently controls the target wheel and other wheels to ensure the shortest braking distance while maintaining vehicle directional stability.

[0144] This embodiment of the disclosure identifies emergency braking conditions and switches control strategies, configuring the braking system to maximize braking performance by targeting the fastest response speed and the largest braking force output, while abandoning energy recovery, thereby ensuring the safety of the vehicle and its occupants.

[0145] Figure 2 This is a flowchart of a control method for a braking system provided in another embodiment of this disclosure. For example... Figure 2 As shown, the method includes the following steps.

[0146] S201. Collect the state parameters of the target wheel and / or the braking system parameters.

[0147] The data collected includes, but is not limited to, sensor signals such as wheel speed, motor speed, and suspension height.

[0148] S202. Determine the braking control strategy corresponding to the target wheel based on the state parameters of the target wheel and / or the braking system parameters.

[0149] For example, the wheel slip ratio, adhesion coefficient and vertical load are estimated based on the state parameters of the target wheel, and the corresponding control strategy is determined based on the estimation results.

[0150] The specific determination method is described in the above embodiments and will not be repeated here.

[0151] S203. Based on the braking control strategy corresponding to the target wheel, generate motor regenerative braking torque command and hydraulic braking torque command.

[0152] Among them, the motor regenerative braking torque command is used to control the output braking torque of the motor braking system, and the hydraulic braking torque command is used to control the output braking torque of the hydraulic braking system.

[0153] S204, Control the motor braking system and hydraulic braking system to brake the target wheel with motor regenerative braking torque command and hydraulic braking torque command.

[0154] Specifically, the regenerative braking torque command of the motor is sent to the motor controller. The motor controller receives the regenerative braking torque command and controls the motor braking system to output the target braking torque through the field-oriented control (FOC) algorithm.

[0155] The hydraulic braking torque command is sent to the hydraulic brake actuator, which precisely controls the wheel cylinder pressure by driving a hydraulic pump through a proportional solenoid valve or a motor.

[0156] For example, each wheel is controlled independently. The hydraulic braking force of the left front wheel is executed by the left front hydraulic brake actuator, the hydraulic braking torque command of the right front wheel is executed by the right front hydraulic brake actuator, the hydraulic braking torque command of the left rear wheel is executed by the left rear hydraulic brake actuator, the hydraulic braking torque command of the right rear wheel is executed by the right rear hydraulic brake actuator, the motor regenerative braking torque command of the left front wheel is executed by the left front motor controller, the motor regenerative braking torque command of the right front wheel is executed by the right front motor controller, the motor regenerative braking torque command of the left rear wheel is executed by the left rear motor controller, and the motor regenerative braking torque command of the right rear wheel is executed by the right rear motor controller.

[0157] S205. Collect the actual motor output torque and wheel cylinder pressure, compare them with the target values ​​corresponding to the motor regenerative braking torque command and the hydraulic braking torque command, and make corrections.

[0158] Specifically, closed-loop correction is performed using a proportional-integral-derivative (PID) controller with a control cycle of 5ms.

[0159] S206. If an abnormal wheel slip ratio or a braking force tracking error exceeding the threshold is detected, a mode switch is triggered, and the corresponding control strategy is executed.

[0160] Figure 3 This is a flowchart of a control method for a braking system provided in another embodiment of this disclosure. For example... Figure 3 As shown, the method includes the following steps.

[0161] S301, Signal Acquisition and Input.

[0162] The collected signals include: driver's braking intention (pedal travel and speed), vehicle status signals (vehicle speed, yaw rate, longitudinal acceleration), road surface adhesion coefficient estimation (based on the slip ratio of each wheel), and motor status signals (motor speed, torque, battery SOC).

[0163] S302, Braking force demand calculation and mode judgment.

[0164] First, the total braking force requirement is calculated based on the pedal travel and vehicle speed. Then, based on the magnitude of the required braking force (with deceleration g as a reference), the braking mode is divided into three modes: light braking, medium-heavy braking, and emergency braking. Simultaneously, based on the ideal braking force curve and dynamic load transfer compensation, the initial torque distribution between the front and rear axles is completed.

[0165] S303. Determine the control strategy for each wheel separately.

[0166] This step employs a four-level progressive four-wheel braking force distribution strategy, see details below. Figure 4 .

[0167] The four-level progressive process sequentially performs basic power allocation, load transfer compensation, slip ratio optimization, and limit coordination, ultimately outputting motor recovery torque commands and hydraulic braking pressure commands, respectively. Under normal operating conditions, the electric motor's power is prioritized for energy recovery; in emergency braking or when the motor's capacity is insufficient, the hydraulic brake supplements or fully assumes the responsibility.

[0168] S304. Execute the control strategy for each wheel separately.

[0169] Specifically, the motor controller receives the regenerative torque command and drives the inverter to generate the required torque through closed-loop control; the hydraulic control unit receives the pressure command and adjusts the wheel cylinder pressure through proportional solenoid valves. Meanwhile, the ABSC system can actively intervene in emergency situations to ensure braking stability.

[0170] S305. Determine the wheel dynamics response data and braking output data.

[0171] Specifically, the braking torque of each wheel is composed of the superposition of the electric braking torque component and the hydraulic braking torque component.

[0172] Furthermore, the control data is adjusted based on the actual braking data output.

[0173] S306, Sensor Feedback and State Estimation.

[0174] By using wheel speed sensors, IMU inertial units, brake pressure sensors, and motor encoders, the vehicle can collect wheel speeds, vehicle acceleration, wheel cylinder pressure, and motor feedback torque in real time. Based on this, the vehicle can calculate slip ratio, estimate road adhesion coefficient, and other state variables, providing feedback information for decision-making in the next control cycle.

[0175] Figure 4 This is a schematic diagram of a four-level progressive four-wheel braking force distribution strategy provided in an embodiment of this disclosure. Figure 4 As shown, the four-level strategies are as follows: L1 Initial Demand Identification and Basic Allocation. In this level, the total braking torque is determined based on the vehicle's braking information during braking. The braking torque corresponding to each axle is then determined based on the vertical load on each axle, thereby determining the braking force of the left and right wheels on each axle. The inputs are the driver's braking intention (reflected in the brake pedal opening and depressor speed) and vehicle speed signal. Based on a preset braking force distribution map, the total braking force demand is calculated. The basic distribution ratio between the front and rear axles is given based on the ideal braking force distribution curve (such as the I-curve) combined with a first correction coefficient, and the basic values ​​of the four-wheel braking force are output. This level is used to complete the conversion from driver intention to overall vehicle braking force demand and provides an initial reference for subsequent allocation.

[0176] Level 2 Road Condition Recognition and Braking Force Correction. In this level, braking force is adjusted based on the road adhesion coefficient corresponding to the wheels on both sides of each axle. The inputs are the road adhesion coefficient and road surface type (e.g., split road surface, manhole cover, speed bump, etc.), which can be obtained through vehicle big data models or onboard sensors. A braking force correction coefficient is calculated based on the current road adhesion conditions, and combined with a second correction coefficient, the base braking force output from the first level is dynamically adjusted, resulting in a corrected braking force output. This level ensures that the braking force distribution can adapt to changes in the road environment. For example, on split road surfaces, the braking force on the lower-adhesion side wheels will be reduced to prevent wheel lock-up.

[0177] L3 Motor Regeneration Capacity Assessment and Priority Allocation. This level determines the maximum available regenerative braking torque. Its inputs include braking system parameters such as motor speed, battery SOC, and motor temperature. It comprehensively assesses the available regenerative braking capacity of each wheel motor and formulates an electric motor power allocation strategy based on energy recovery priorities. This level determines the upper limit of braking force that the electric motor braking system can handle while meeting braking requirements, providing a basis for subsequent electro-hydraulic coordinated allocation.

[0178] L4 Dynamic Optimization and Safety Constraints. This level is applied to safety-priority scenarios such as low-traction anti-skid and emergency braking. Its inputs are the ABS intervention status, tire temperature, and other vehicle stability states. While satisfying the electro-hydraulic distribution ratios of the aforementioned levels, it introduces safety constraints such as yaw moment limits and slip ratio limits, and finally outputs independent electric motor braking control commands and hydraulic braking control commands for each wheel.

[0179] Figure 5 This is a diagram of the target wheel closed-loop control architecture provided in an embodiment of this disclosure. Figure 5 As shown, the control process begins with the target braking command, which is the target braking force determined for the target wheel in step S110. The target braking command first enters the slip ratio controller, which calculates the desired braking force adjustment amount using algorithms such as adaptive PID control or sliding mode control based on the deviation between the desired slip ratio and the actual estimated slip ratio. Simultaneously, the slip ratio controller also includes feedforward compensation, which pre-calculates the basic control quantity based on parameters such as vehicle speed, vehicle mass, and vertical load to accelerate the system's response speed and reduce the burden on feedback control.

[0180] Subsequently, the adjustment is sent to the electro-hydraulic actuator, which, based on the current operating conditions and motor capacity, splits the total braking force command into two parallel commands: motor braking and hydraulic braking, and outputs them separately. Specifically, the motor braking channel outputs a torque command to the motor, while the hydraulic braking channel outputs a pressure command to the hydraulic actuator. Together, they act on the wheel dynamics model, causing the wheel to generate the actual braking torque.

[0181] The actual motion of the wheels (such as wheel speed) is measured by wheel speed sensors, while the vehicle speed is estimated by an IMU. Both are input into the slip ratio estimation module to calculate the actual longitudinal slip ratio of the current wheels. Simultaneously, the road surface adhesion coefficient identification module estimates the current road surface adhesion coefficient online in real time based on the ratio of actual braking force to vertical load using algorithms such as recursive least squares or Kalman filtering. It can also adaptively adjust based on the road surface adhesion coefficient-longitudinal slip ratio mapping curve to provide more accurate adhesion information. The actual slip ratio and the estimated adhesion coefficient are fed back to the slip ratio controller, compared with the desired slip ratio, forming a closed-loop correction.

[0182] Figure 6 This is a schematic diagram of the structure of a control device for a braking system provided in an embodiment of this disclosure.

[0183] In this embodiment of the disclosure, the control device of the braking system may be located within an electronic device and can be understood as a part of the functional modules in the aforementioned electronic device.

[0184] like Figure 6 As shown, the control device 60 of the braking system may include a first determining module 61, a second determining module 62, and a control module 63; wherein, the first determining module 61 is used to determine the target braking force corresponding to each wheel based on the braking information of the vehicle during braking; the second determining module 62 is used to determine the braking control strategy corresponding to the target wheel according to the state parameters of the target wheel and / or the braking system parameters, and the braking control strategy is used to make the braking force of the target wheel reach the target braking force; the control module 63 is used to control the braking torque output by the vehicle's electric braking system and / or hydraulic braking system to the target wheel according to the braking control strategy.

[0185] In some embodiments, the first determining module 61 includes a first determining unit and a second determining unit; the first determining unit is used to determine the total braking torque of the vehicle based on the braking information of the vehicle during braking, the braking information including the brake pedal opening, the braking pedal depressing rate, the vehicle speed, and the vehicle mass; the second determining unit is used to determine the target braking force corresponding to each wheel according to the total braking torque, wherein the sum of the target braking forces corresponding to each wheel is the braking force corresponding to the total braking torque.

[0186] In some embodiments, the second determining unit is used to distribute the total braking torque to each axle according to the vertical load of each axle of the vehicle and a first correction coefficient, to obtain the braking torque corresponding to each axle. The sum of the braking torques corresponding to each axle is used to make the braking force of the vehicle reach the braking force corresponding to the total braking torque. The first correction coefficient is used to make the distribution ratio of each axle to the total braking torque within a preset safety range. For each axle, the braking torque corresponding to the axle is distributed to multiple wheels corresponding to the axle to obtain the target braking torque corresponding to each wheel. The target braking torque is used to provide the target braking force to the target wheel.

[0187] In some embodiments, the second determining unit is used to allocate the braking torque corresponding to the axle based on the road surface adhesion coefficient corresponding to each wheel and the second correction coefficient, so as to obtain the target braking torque corresponding to each wheel. The second correction coefficient is used to control the yaw torque generated by the braking force difference between the two wheels on the same axle to be less than a preset safety threshold.

[0188] In some embodiments, the state parameters include longitudinal slip ratio and road surface adhesion coefficient. The second determining module 62 includes a first strategy determining unit 621, which is used to determine the braking control strategy corresponding to the target wheel as the first control strategy when the absolute value of the longitudinal slip ratio of the target wheel is less than the lower limit of a preset slip ratio range and the road surface adhesion coefficient corresponding to the target wheel is greater than the upper limit of a preset coefficient range. The control module 63 includes a first control unit 631, which is used to control the electric motor braking system to output a first target torque to the target wheel when the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the first target torque. The first target torque is used to make the braking force of the target wheel reach the target braking force. When the maximum available regenerative braking torque corresponding to the target wheel is less than the first target torque, the electric motor braking system is controlled to output the maximum available regenerative braking torque to the target wheel, and the hydraulic braking system is controlled to output a first compensation torque to the target wheel. The sum of the maximum available regenerative braking torque and the first compensation torque is used to make the braking force of the target wheel reach the target braking force.

[0189] In some embodiments, the state parameters include longitudinal slip ratio and road surface adhesion coefficient. The second determining module 62 includes a second strategy determining unit 622, which is used to determine the braking control strategy corresponding to the target wheel as the second control strategy when the absolute value of the longitudinal slip ratio of the target wheel is greater than the upper limit of the preset slip ratio range and the corresponding road surface adhesion coefficient of the target wheel is less than the lower limit of the preset coefficient range. The control module 63 includes a second control unit 631, which is used to reduce the target braking force; control the hydraulic braking system to reduce the braking torque output to the target wheel, control the electric motor braking system to increase the braking torque output to the target wheel, and the sum of the braking torque output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force and reduce the longitudinal slip ratio of the target wheel to the preset coefficient range.

[0190] In some embodiments, the state parameters include vertical load. The second determining module 62 includes a third strategy determining unit 623, which is used to determine the braking control strategy corresponding to the target wheel as a third control strategy when there is a pothole on the road surface in the direction of travel of the target wheel that reduces the vertical load of the target wheel and the rate of change is greater than a first load change rate threshold. The control module 63 includes a third control unit 633, which is used to reduce the target braking force; control the hydraulic braking system to reduce the rate of change of the output torque of the target wheel to a preset rate of change threshold, control the electric motor braking system to adjust the braking torque output to the target wheel, and the sum of the braking torque output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force.

[0191] In some embodiments, the state parameters include vertical load. The second determining module 62 includes a fourth strategy determining unit 624, which determines the braking control strategy corresponding to the target wheel as the fourth control strategy when there is an obstacle on the road surface in the direction of travel of the target wheel that increases the vertical load of the target wheel and the rate of change is greater than the second load change rate threshold. The control module 63 includes a fourth control unit 634, which is used to reduce the target braking force. When the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the second target torque, the control motor braking system is controlled to output the second target torque to the target wheel. The second target torque is used to make the braking force of the target wheel reach the reduced target braking force. When the maximum available regenerative braking torque corresponding to the target wheel is less than the second target torque, the control motor braking system is controlled to output the maximum available regenerative braking torque to the target wheel, and the control hydraulic braking system is controlled to output the second compensation torque to the target wheel. The sum of the maximum available regenerative braking torque and the second compensation torque is used to make the braking force of the target wheel reach the reduced target braking force.

[0192] In some embodiments, the fourth control unit 634 is further configured to restore the reduced target braking force to the target braking force according to a preset recovery rate when the target wheel passes over an obstacle.

[0193] In some embodiments, the braking system parameters include the temperature of the motor and / or the battery level of the vehicle. The second determining module 62 includes a fifth strategy determining unit 625, which is used to determine the braking control strategy corresponding to the target wheel as the fifth control strategy when the temperature of the vehicle's motor is greater than a preset temperature threshold or the battery level of the vehicle reaches its maximum. The control module 63 includes a fifth control unit 625, which is used to control the braking torque output by the motor braking system to the target wheel to be reduced to zero, and the duration of the reduction of the braking torque output by the motor braking system to the target wheel is greater than a preset time threshold. The control module 63 also controls the hydraulic braking system to output a third compensation torque to the target wheel, and the sum of the braking torque output by the motor braking system to the target wheel and the third compensation torque is used to make the braking force of the target wheel reach the target braking force.

[0194] In some embodiments, the braking system parameters include the braking pedal depressing rate. The second determining module 62 includes a sixth strategy determining unit 626, used to determine the braking control strategy corresponding to the target wheel as the sixth control strategy when the braking pedal depressing rate of the vehicle is greater than a preset rate threshold. The control module 63 includes a sixth control unit 636, used to control the hydraulic braking system to output a third target torque to the target wheel when the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is greater than or equal to the third target torque. The third target torque is used to make the braking force of the target wheel reach the target braking force. When the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is less than the third target torque, the hydraulic braking system is controlled to output a maximum braking torque to the target wheel, and the electric motor braking system is controlled to output a fourth compensation torque to the target wheel. The sum of the maximum hydraulic braking torque and the fourth compensation torque is used to make the braking force of the target wheel reach the target braking force.

[0195] It should be noted that, Figure 6 The control device 60 of the braking system shown can execute the various steps in the above method embodiments and realize the various processes and effects in the above method embodiments, which will not be elaborated here.

[0196] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this disclosure.

[0197] like Figure 7 As shown, the electronic device may include a processor 710 and a memory 720 storing computer program instructions.

[0198] Specifically, the processor 710 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this disclosure.

[0199] Memory 720 may include a large-capacity storage for information or instructions. For example, and not limitingly, memory 720 may include a hard disk drive (HDD), a floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 720 may include removable or non-removable (or fixed) media. Where appropriate, memory 720 may be internal or external to the integrated gateway device. In a particular embodiment, memory 720 is a non-volatile solid-state memory. In a particular embodiment, memory 720 includes read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (Electrically Programmable ROM, EPROM), an electrically erasable programmable PROM (EEPROM), an electrically alterable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0200] The processor 710 reads and executes computer program instructions stored in the memory 720 to perform the steps of the control method for the braking system provided in the embodiments of this disclosure.

[0201] In one example, the electronic device may also include a transceiver 730 and a bus 740. Wherein, as... Figure 7 As shown, the processor 710, memory 720 and transceiver 730 are connected via bus 740 and communicate with each other.

[0202] Bus 740 may include hardware, software, or both. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 740 may include one or more buses.

[0203] This disclosure also provides a computer-readable storage medium that can store a computer program, which, when executed by a processor, enables the processor to implement the control method of the braking system provided in this disclosure.

[0204] The aforementioned storage medium may, for example, include a memory 720 containing computer program instructions, which can be executed by a processor 710 of an electronic device to complete the control method of the braking system provided in the embodiments of this disclosure. Optionally, the storage medium may be a non-transitory computer-readable storage medium, such as a ROM, random access memory (RAM), compact disc ROM (CD-ROM), magnetic tape, floppy disk, and optical data storage device.

[0205] This disclosure also provides a vehicle that includes electronic devices that can implement the various processes and effects described in the above embodiments of this disclosure, which will not be elaborated here.

[0206] This disclosure also provides a computer program product, which includes a computer program or instructions. When the computer program or instructions are executed by a processor, they implement the control method of the braking system provided in this disclosure and can achieve the various processes and effects in the above embodiments of this disclosure, which will not be elaborated here.

[0207] 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 control method for a braking system, characterized in that, include: Based on the vehicle's braking information during braking, the target braking force corresponding to each wheel is determined; The braking control strategy corresponding to the target wheel is determined based on the state parameters of the target wheel and / or the braking system parameters. The braking control strategy is used to make the braking force of the target wheel reach the target braking force. According to the braking control strategy, the braking torque output by the vehicle's electric braking system and / or hydraulic braking system to the target wheel is controlled.

2. The method according to claim 1, characterized in that, The determination of the target braking force for each wheel based on the vehicle's braking information during braking includes: Based on the vehicle's braking information during braking, the total braking torque of the vehicle is determined. The braking information includes the brake pedal opening, the rate at which the brake pedal is depressed, the vehicle speed, and the vehicle mass. Based on the total braking torque, the target braking force corresponding to each wheel is determined, and the sum of the target braking forces corresponding to each wheel is the braking force corresponding to the total braking torque.

3. The method according to claim 2, characterized in that, The step of determining the target braking force for each wheel based on the total braking torque includes: The total braking torque is distributed to each axle based on the vertical load of each axle of the vehicle and a first correction coefficient, resulting in a braking torque corresponding to each axle. The sum of the braking torques corresponding to each axle is used to make the braking force of the vehicle reach the braking force corresponding to the total braking torque. The first correction coefficient is used to ensure that the distribution ratio of each axle to the total braking torque is within a preset safety range. For each axle, the braking torque corresponding to the axle is distributed to the multiple wheels corresponding to the axle to obtain the target braking torque corresponding to each wheel. The target braking torque is used to provide target braking force to the target wheel.

4. The method according to claim 3, characterized in that, The step of distributing the braking torque corresponding to the axle to the multiple wheels corresponding to the axle, to obtain the target braking torque corresponding to each wheel, includes: The braking torque corresponding to the axle is allocated based on the road adhesion coefficient and the second correction coefficient for each wheel to obtain the target braking torque for each wheel. The second correction coefficient is used to control the yaw torque generated by the braking force difference between the two wheels on the same axle to be less than a preset safety threshold.

5. The method according to any one of claims 1-4, characterized in that, The state parameters include longitudinal slip ratio and road surface adhesion coefficient. Based on the state parameters of the target wheel, a braking control strategy corresponding to the target wheel is determined, including: If the absolute value of the longitudinal slip ratio of the target wheel is less than the lower limit of the preset slip ratio range, and the road surface adhesion coefficient corresponding to the target wheel is greater than the upper limit of the preset coefficient range, then the braking control strategy corresponding to the target wheel is determined to be the first control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: When the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the first target torque, the motor braking system is controlled to output the first target torque to the target wheel. The first target torque is used to make the braking force of the target wheel reach the target braking force. When the maximum available regenerative braking torque corresponding to the target wheel is less than the first target torque, the electric motor braking system is controlled to output the maximum available regenerative braking torque to the target wheel, and the hydraulic braking system is controlled to output a first compensation torque to the target wheel. The sum of the maximum available regenerative braking torque and the first compensation torque is used to make the braking force of the target wheel reach the target braking force.

6. The method according to any one of claims 1-4, characterized in that, The state parameters include longitudinal slip ratio and road surface adhesion coefficient. Based on the state parameters of the target wheel, a braking control strategy corresponding to the target wheel is determined, including: If the absolute value of the longitudinal slip ratio of the target wheel is greater than the upper limit of the preset slip ratio range, and the road surface adhesion coefficient corresponding to the target wheel is less than the lower limit of the preset coefficient range, then the braking control strategy corresponding to the target wheel is determined to be the second control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: Reduce the target braking force; The hydraulic braking system is controlled to reduce the braking torque output to the target wheel, and the electric motor braking system is controlled to increase the braking torque output to the target wheel. The sum of the braking torque output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force, and to reduce the longitudinal slip ratio of the target wheel to the preset coefficient range.

7. The method according to any one of claims 1-4, characterized in that, The state parameters include vertical load. Based on the state parameters of the target wheel, a braking control strategy corresponding to the target wheel is determined, including: If there is a pothole on the road surface in the direction of travel of the target wheel that reduces the vertical load of the target wheel and the rate of change is greater than the first load change rate threshold, the braking control strategy corresponding to the target wheel is determined to be the third control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: Reduce the target braking force; The rate of change of the output torque of the hydraulic braking system on the target wheel is reduced to below a preset rate of change threshold. The electric motor braking system is then controlled to adjust the braking torque output to the target wheel. The sum of the braking torques output by the electric motor braking system and the electric motor braking system is used to make the braking force of the target wheel reach the reduced target braking force.

8. The method according to any one of claims 1-4, characterized in that, The state parameters include vertical load. Based on the state parameters of the target wheel, a braking control strategy corresponding to the target wheel is determined, including: If there is an obstacle on the road surface in the direction of travel of the target wheel that increases the vertical load of the target wheel and the rate of change is greater than the second load change rate threshold, the braking control strategy corresponding to the target wheel is determined to be the fourth control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: Reduce the target braking force; When the maximum available regenerative braking torque corresponding to the target wheel is greater than or equal to the second target torque, the motor braking system is controlled to output the second target torque to the target wheel. The second target torque is used to make the braking force of the target wheel reach the reduced target braking force. When the maximum available regenerative braking torque corresponding to the target wheel is less than the second target torque, the electric motor braking system is controlled to output the maximum available regenerative braking torque to the target wheel, and the hydraulic braking system is controlled to output the second compensation torque to the target wheel. The sum of the maximum available regenerative braking torque and the second compensation torque is used to make the braking force of the target wheel reach the reduced target braking force.

9. The method according to claim 8, characterized in that, After the electric braking system and / or hydraulic braking system controlling the vehicle brakes the target wheel, the method further includes: When the target wheel passes the obstacle, the reduced target braking force is restored to the target braking force according to a preset recovery rate.

10. The method according to any one of claims 1-4, characterized in that, The braking system parameters include the motor temperature and / or the vehicle's battery level. Based on these parameters, a braking control strategy is determined for the target wheel, including: If the temperature of the vehicle's motor is greater than a preset temperature threshold, or if the vehicle's battery level reaches its maximum, the braking control strategy corresponding to the target wheel is determined to be the fifth control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: The braking torque output by the motor braking system to the target wheel is reduced to zero, and the duration for which the motor braking system reduces the braking torque output to the target wheel is greater than a preset time threshold. The hydraulic braking system is controlled to output a third compensating torque to the target wheel. The sum of the braking torque output by the electric braking system to the target wheel and the third compensating torque is used to make the braking force of the target wheel reach the target braking force.

11. The method according to any one of claims 1-4, characterized in that, Braking system parameters include the brake pedal depress rate. Based on these parameters, a braking control strategy is determined for the target wheel, including: If the braking pedal depressing rate of the vehicle is greater than a preset rate threshold, the braking control strategy corresponding to the target wheel is determined to be the sixth control strategy. The step of controlling the vehicle's electric braking system and / or hydraulic braking system to brake the target wheel according to the braking control strategy includes: When the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is greater than or equal to the third target torque, the hydraulic braking system is controlled to output the third target torque to the target wheel, and the third target torque is used to make the braking force of the target wheel reach the target braking force. When the maximum hydraulic braking torque output by the hydraulic braking system to the target wheel is less than the third target torque, the hydraulic braking system is controlled to output the maximum braking torque to the target wheel, and the electric motor braking system is controlled to output the fourth compensation torque to the target wheel. The sum of the maximum hydraulic braking torque and the fourth compensation torque is used to make the braking force of the target wheel reach the target braking force.

12. A vehicle, characterized in that, The vehicle includes electronic equipment, which includes: processor; Memory, used to store executable instructions; The processor is configured to read the executable instructions from the memory and execute the executable instructions to implement the method of any one of claims 1-11.

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