Vehicle brake slip control method, system, vehicle and storage medium

Abstract

The application discloses a vehicle brake anti-skid control method and system, a vehicle and a storage medium, wherein the method comprises the following steps: acquiring driving data and basic data of the vehicle, wherein the driving data comprises vehicle speed, acceleration, steering wheel rotation angle, yaw angular velocity and actual wheel speed, and the basic data comprises wheelbase and track; determining a slip state of the electric vehicle according to the driving data and the basic data, wherein the slip state comprises brake slip and non-slip; determining a target single-wheel output brake torque in response to the slip state being brake slip; determining a target brake torque limit value of a power motor in response to the slip state being brake slip; and controlling the electric vehicle according to the target single-wheel output brake torque and the target brake torque limit value. The application solves the technical problem that, in the prior art, due to a large delay of hydraulic response, the control effect is poor, and it is difficult to meet the requirements of users for driving quality and driving safety.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control technology, and more specifically, relates to a vehicle braking anti-skid control method, system, vehicle, and storage medium. Background Technology

[0002] Currently, the industry mainly uses hydraulic brake anti-skid control systems. When tires slip during braking, the system dynamically adjusts the hydraulic brakes to reduce slippage and release the slippage state. However, due to the significant delay in hydraulic response and poor control effect, this strategy tends to result in frequent and repeated engagement and disengagement of the anti-lock braking function, wheel lock-up fluctuations, and longitudinal deceleration fluctuations when driving on wet and slippery surfaces. This is detrimental to the overall drivability and stability of the vehicle and can no longer meet the increasingly demanding requirements of users for driving quality and safety. Summary of the Invention

[0003] This invention provides a vehicle braking anti-skid control method, system, vehicle, and storage medium to at least solve the technical problem in the prior art where the large delay in hydraulic response results in poor control performance, making it difficult to meet users' increasingly demanding requirements for driving quality and driving safety.

[0004] According to a first aspect of the present invention, a vehicle braking anti-skid control method is provided, comprising: acquiring vehicle driving data and basic data, wherein the driving data includes vehicle speed, acceleration, steering wheel angle, yaw rate and actual wheel speed, and the basic data includes wheelbase and track width; determining a slip state of an electric vehicle based on the driving data and basic data, wherein the slip state includes brake slip and no slip; determining a target single-wheel output braking torque in response to the slip state being brake slip; determining a target braking torque limit for a power motor in response to the slip state being brake slip; and controlling the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0005] Optionally, determining the slip state of an electric vehicle based on driving data and basic data includes: determining the target slip ratio of the wheels based on acceleration; determining the actual slip ratio and wheel speed difference of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data; and determining the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel, and preset judgment rules.

[0006] Optionally, the actual slip ratio of each wheel can be determined based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data, including: determining the reference wheel speed of each wheel based on vehicle speed, steering wheel angle, yaw rate, and basic data; and determining the actual slip ratio of each wheel based on the reference wheel speed and the actual wheel speed of each wheel.

[0007] Optionally, the wheel speed difference of each wheel can be determined based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data, including: determining the reference wheel speed of each wheel based on vehicle speed, steering wheel angle, yaw rate, and basic data; determining the target wheel speed of each wheel based on the target slip ratio and the reference wheel speed of each wheel; and determining the wheel speed difference based on the target wheel speed and the actual wheel speed.

[0008] Optionally, the preset judgment rules include a first judgment rule and a second judgment rule. The first judgment rule determines the slip state of the electric vehicle based on the target slip ratio and the actual slip ratio of each wheel. The second judgment rule determines the slip state of the electric vehicle based on the wheel speed difference of each wheel. Determining the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel, and the preset judgment rules includes: determining the slip state of the electric vehicle as braking slip in response to the target slip ratio and the actual slip ratio of each wheel satisfying the first judgment rule, or determining the slip state of the electric vehicle as braking slip in response to the wheel speed difference of each wheel satisfying the second judgment rule.

[0009] Optionally, in response to the slip state being braking slip, determining the target single-wheel output braking torque includes: in response to the slip state being braking slip, determining the road surface adhesion coefficient; and determining the target single-wheel output braking torque based on the road surface adhesion coefficient.

[0010] Optionally, in response to the slip state being brake slip, determining the target braking torque limit of the power motor includes: in response to the slip state being brake slip, determining the wheel speed difference; and determining the target braking torque limit of the power motor based on the wheel speed difference.

[0011] According to a second aspect of the present invention, a vehicle braking anti-skid control system is also provided, comprising:

[0012] The system comprises the following modules: an acquisition module for acquiring vehicle driving data and basic data, including vehicle speed, acceleration, steering wheel angle, yaw rate, and actual wheel speed; a first determination module for determining the slip state of the electric vehicle based on the driving data and basic data, including braked slip and no slip; a second determination module for determining the target single-wheel output braking torque in response to the slip state being braked slip; a third determination module for determining the target braking torque limit of the power motor in response to the slip state being braked slip; and a control module for controlling the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0013] Optionally, the first determining module is also used to: determine the target slip ratio of the wheels based on acceleration; determine the actual slip ratio and wheel speed difference of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed and basic data; and determine the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel and preset judgment rules.

[0014] Optionally, the first determining module is also used to: determine the reference wheel speed of each wheel based on the vehicle speed, steering wheel angle, yaw rate and basic data; and determine the actual slip ratio of each wheel based on the reference wheel speed and the actual wheel speed of each wheel.

[0015] Optionally, the first determining module is also used to: determine the reference wheel speed of each wheel based on the vehicle speed, steering wheel angle, yaw rate and basic data; determine the target wheel speed of each wheel based on the target slip ratio and the reference wheel speed of each wheel; and determine the wheel speed difference based on the target wheel speed and the actual wheel speed.

[0016] Optionally, the preset determination rules include a first determination rule and a second determination rule, wherein the first determination rule determines the slip state of the electric vehicle based on the target slip ratio and the actual slip ratio of each wheel, and the second determination rule determines the slip state of the electric vehicle based on the wheel speed difference of each wheel; the first determination module is further configured to: determine the slip state of the electric vehicle as braking slip in response to the target slip ratio and the actual slip ratio of each wheel satisfying the first determination rule, or determine the slip state of the electric vehicle as braking slip in response to the wheel speed difference of each wheel satisfying the second determination rule.

[0017] Optionally, the second determining module is also used to: determine the road surface adhesion coefficient in response to the slip state being braking slip; and determine the target single-wheel output braking torque based on the road surface adhesion coefficient.

[0018] Optionally, the third determining module is also used to: determine the wheel speed difference in response to the slip state being braking slip; and determine the target braking torque limit of the power motor based on the wheel speed difference.

[0019] According to a third aspect of the present invention, a vehicle is also provided, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the vehicle braking anti-skid control method described in any of the embodiments of the first aspect.

[0020] According to a fourth aspect of the present invention, a non-volatile storage medium is also provided, wherein a computer program is stored in the non-volatile storage medium, wherein the computer program is configured to execute the vehicle braking anti-skid control method described in any embodiment of the first aspect when running on a computer or processor.

[0021] In this embodiment of the invention, vehicle driving data and basic data are acquired. The driving data includes vehicle speed, acceleration, steering wheel angle, yaw rate, and actual wheel speed. The basic data includes wheelbase and track width. Based on the driving data and basic data, the slip state of the electric vehicle is determined, including brake slip and no slip. In response to brake slip, a target single-wheel output braking torque is determined. Also in response to brake slip, a target braking torque limit for the power motor is determined. The electric vehicle is controlled based on the target single-wheel output braking torque and the target braking torque limit. When brake slip occurs, this method coordinates the control of hydraulic braking and electric motor braking based on the target single-wheel output braking torque and the target braking torque limit. In this coordinated control, the motor control response is faster than the hydraulic braking response, thus solving the technical problem in the prior art where the hydraulic response has a large delay, resulting in poor control performance and failing to meet users' increasingly demanding requirements for driving quality and safety. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0023] Figure 1 This is a flowchart of a vehicle braking anti-skid control method according to one embodiment of the present invention;

[0024] Figure 2 This is a structural block diagram of a vehicle braking anti-skid control system according to one embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] According to an embodiment of the present invention, an embodiment of a vehicle braking anti-skid control method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system containing at least a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0028] This method embodiment can also be executed in an electronic device including a memory and a processor, a similar control device, or in the cloud. Taking an electronic device as an example, the electronic device may include one or more processors and a memory for storing data. Optionally, the electronic device may also include a communication device for communication functions and a display device. Those skilled in the art will understand that the above structural description is merely illustrative and does not limit the structure of the electronic device. For example, the electronic device may include more or fewer components than described above, or have a different configuration than described above.

[0029] A processor may include one or more processing units. For example, a processor may include a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processing (DSP) chip, a microcontroller unit (MCU), a field-programmable gate array (FPGA), a neural network processing unit (NPU), a tensor processing unit (TPU), or an artificial intelligence (AI) processor. Different processing units may be independent components or integrated into one or more processors. In some instances, electronic devices may also include one or more processors.

[0030] The memory can be used to store computer programs, such as the computer program corresponding to the vehicle braking anti-skid control method in this embodiment of the invention. The processor implements the aforementioned vehicle braking anti-skid control method by running the computer program stored in the memory. The memory may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to electronic devices via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0031] The communication device is used to receive or send data via a network. Specific examples of the network mentioned above may include a wireless network provided by the mobile terminal's communication provider. In one example, the communication device includes a network interface controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the communication device may be a radio frequency (RF) module, used for wireless communication with the Internet. In some embodiments of this solution, the communication device is used to connect to mobile devices such as mobile phones and tablets, enabling the mobile device to send commands to the electronic device.

[0032] The display device can be a touchscreen liquid crystal display (LCD) or a touch display (also referred to as a "touchscreen" or "touch display screen"). The LCD allows a user to interact with the user interface of the electronic device. In some embodiments, the electronic device has a graphical user interface (GUI), which allows the user to interact with the GUI by touching a touch-sensitive surface with fingers and / or gestures. Executable instructions for performing these human-computer interaction functions are configured / stored in one or more processor-executable computer program products or readable storage media.

[0033] Figure 1 This is a flowchart of a vehicle braking anti-skid control method according to one embodiment of the present invention, such as... Figure 1 As shown, the method includes the following steps:

[0034] Step S101: Obtain vehicle driving data and basic data.

[0035] The driving data includes vehicle speed, acceleration, steering wheel angle, yaw rate, and actual wheel speed, while the basic data includes wheelbase and track width.

[0036] Specifically, the actual wheel speed refers to the wheel speed calculated based on the signal from the wheel speed sensor currently being acquired.

[0037] It should be noted that wheelbase refers to the distance from the center of the front axle to the center of the rear axle, while track width refers to the distance between the center lines of the tracks left by the wheels on the vehicle's supporting plane.

[0038] Step S102: Determine the slip state of the electric vehicle based on the driving data and basic data.

[0039] The slip state includes braking slip and no slip.

[0040] Specifically, once the vehicle's driving data and basic data are obtained, the current slip state of the vehicle can be determined using a preset slip state determination method, for example, the current slip state of the vehicle can be determined to be braking slip.

[0041] It is understandable that when a vehicle's slip state is described as "braking slip," it means that the vehicle has engaged in braking slip.

[0042] It's important to note that brake slip refers to the relative speed difference between the wheels and the road surface when a vehicle brakes. When a vehicle brakes, slippage occurs between the wheels and the road surface; that is, there is a difference between the wheel's rotational speed and the road surface's moving speed. The magnitude of brake slip depends on factors such as braking force, the road surface friction coefficient, and wheel rotational speed. Excessive brake slip can lead to increased braking distance, reduced braking effectiveness, and may even cause loss of vehicle control. Therefore, controlling brake slip is crucial in vehicle braking system design and driving to improve braking effectiveness and safety.

[0043] Step S103: In response to the slip state being braking slip, determine the target single wheel output braking torque.

[0044] Specifically, when the vehicle is in a braking slip state, the target single-wheel output braking torque can be determined based on the driving data and basic data obtained above, using a preset single-wheel output braking torque calculation method.

[0045] It should be noted that single-wheel output braking torque refers to the braking torque transmitted to the ground through the wheels during vehicle braking. This target single-wheel output braking torque can be used to limit the torque required for hydraulic braking.

[0046] Step S104: In response to the slip state being brake slip, determine the target braking torque limit of the power motor.

[0047] Specifically, when the vehicle is in a braking slip state, the target braking torque limit can be determined based on the driving data and basic data obtained above, using a preset calculation method for the target braking torque limit of the power motor. This target braking torque limit can be used to limit the braking torque demand of the power motor.

[0048] Step S105: Control the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0049] Specifically, by obtaining the target single-wheel output braking torque and the target braking torque limit, the hydraulic system and power motor in the electric vehicle can be controlled based on the target single-wheel output braking torque and the target braking torque limit.

[0050] In this embodiment of the invention, vehicle driving data and basic data are acquired. The driving data includes vehicle speed, acceleration, steering wheel angle, yaw rate, and actual wheel speed. The basic data includes wheelbase and track width. Based on the driving data and basic data, the slip state of the electric vehicle is determined, including brake slip and no slip. In response to brake slip, a target single-wheel output braking torque is determined. Also in response to brake slip, a target braking torque limit for the power motor is determined. The electric vehicle is controlled based on the target single-wheel output braking torque and the target braking torque limit. When brake slip occurs, this method coordinates the control of hydraulic braking and electric motor braking based on the target single-wheel output braking torque and the target braking torque limit. In this coordinated control, the motor control response is faster than the hydraulic braking response, thus solving the technical problem in the prior art where the hydraulic response has a large delay, resulting in poor control performance and failing to meet users' increasingly demanding requirements for driving quality and safety.

[0051] Optionally, in step S102, determining the slip state of the electric vehicle based on the driving data and the basic data may include the following steps:

[0052] Step S1021: Determine the target slip ratio of the wheel based on the acceleration.

[0053] Specifically, the road surface adhesion coefficient is first determined based on acceleration, which includes lateral acceleration and longitudinal acceleration. The formula for determining the road surface adhesion coefficient is as follows:

[0054]

[0055] Where μ is the road surface adhesion coefficient, a x For lateral acceleration, a y Where g is the longitudinal acceleration and g is the gravitational acceleration. Once the road surface adhesion coefficient is determined, the target slip ratio reference table preset in the vehicle can be consulted based on the road surface adhesion coefficient. The target slip ratio reference table is obtained through calibration, and the target slip ratio of the wheel can be obtained by looking up the table using the road surface adhesion coefficient.

[0056] It should be noted that each wheel has its own target slip ratio reference table, and this step requires determining the target slip ratio for each wheel. Under most braking conditions, the target slip ratio of the front wheels is greater than that of the rear wheels.

[0057] It should be noted that the target slip ratio can be understood as the optimal longitudinal and lateral adhesion capability that the vehicle can achieve at that target slip ratio.

[0058] Understandably, on high-friction surfaces, the adhesion between the wheels and the road surface is relatively large, and the actual slip ratio is relatively small. If a smaller initial target torque is set based on the target slip ratio, good acceleration performance cannot be obtained. On low-friction surfaces, the adhesion between the wheels and the road surface is relatively small, and the actual slip ratio is relatively large. If a larger initial target torque is set based on the target slip ratio, severe slippage will occur.

[0059] Step S1022: Determine the actual slip ratio and wheel speed difference of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data.

[0060] Specifically, after determining the target slip ratio for each wheel, the actual slip ratio and wheel speed difference for each wheel can be determined using a preset calculation method based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data.

[0061] It should be noted that the actual slip ratio refers to the proportion of slip component in the actual wheel movement of a vehicle under its current state. A higher slip ratio indicates a higher proportion of slip component in wheel movement, while a lower slip ratio indicates a lower proportion of slip component. Wheel speed difference refers to the difference between the target wheel speed and the actual wheel speed; the target wheel speed is the wheel speed that the vehicle hopes to achieve.

[0062] Step S1023: Determine the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel, and the preset judgment rules.

[0063] Understandably, by matching the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel with the preset judgment rules, the slip state of the electric vehicle can be determined.

[0064] It should be noted that the preset judgment rules define the judgment rules for whether an electric vehicle is in a slipping state. The target slip ratio, the actual slip ratio of each wheel, and the wheel speed difference of each wheel are the basis for the judgment.

[0065] Optionally, in step S1022, determining the actual slip ratio of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data may include the following steps:

[0066] Step S1022a: Determine the reference wheel speed for each wheel based on the vehicle speed, steering wheel angle, yaw rate, and basic data.

[0067] Specifically, the formula for calculating the reference wheel speed for each wheel is as follows:

[0068]

[0069]

[0070]

[0071]

[0072] Among them, v fl_ref The reference speed for the left front wheel is (m / s), v fr_ref Reference wheel speed for the right front wheel (m / s); v rl_ref The reference wheel speed for the left rear wheel is v (m / s). rr_ref Here, L is the reference wheel speed for the right rear wheel (m / s), b is the wheelbase (m), δ is the wheel moment (m), and δ is the front wheel steering angle (rad). This represents the yaw rate (rad / s). The units within parentheses are for the parameters.

[0073] Step S1022b: Determine the actual slip ratio of each wheel based on the reference wheel speed and the actual wheel speed of each wheel.

[0074] Specifically, the formula for calculating the actual slip ratio of each wheel is as follows:

[0075] λ fl =(v fl_ref -v fl ) / v fl_ref

[0076] λ fr =(v fr_ref -v fr ) / v fr_ref

[0077] λ rl =(v rl_ref -v rl ) / v rl_ref

[0078] λ rr =(v rr_ref -v rr ) / v rr_ref

[0079] Among them, v fl v represents the actual wheel speed of the left front wheel (m / s). fr v represents the actual wheel speed of the right front wheel (m / s). rl v represents the actual wheel speed of the left rear wheel (m / s). rr λ represents the actual wheel speed of the right rear wheel (m / s). fl λ represents the actual slip ratio of the left front wheel. fr λ represents the actual slip ratio of the right front wheel. rl λ represents the actual slip ratio of the left rear wheel. rr This represents the actual slip ratio of the right rear wheel.

[0080] Optionally, in step S1022, determining the wheel speed difference of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed, and basic data may include the following steps:

[0081] Step S1022a: Determine the reference wheel speed for each wheel based on the vehicle speed, steering wheel angle, yaw rate, and basic data.

[0082] Step S1022c: Determine the target wheel speed for each wheel based on the target slip ratio and the reference wheel speed for each wheel.

[0083] Specifically, the formula for calculating the target wheel speed for each wheel is as follows:

[0084] v tgt_fl =v fl_ref (1+λ tgt_fl )

[0085] v tgt_fr =v fr_ref (1+λ tgt_fr )

[0086] v tgt_rl =v rl_ref (1+λ tgt_rl )

[0087] v tgt_rr =v rr_ref (1+λ tgt_rr )

[0088] Among them, v tgt_fl The target speed of the left front wheel (m / s), v tgt_fr The target speed of the right front wheel (m / s), v tgt_rl The target speed of the left rear wheel (m / s), v tgt_rr λ represents the reference speed of the right rear wheel (m / s). tgt_fl Let λ be the target slip ratio of the left front wheel. tgt_fr Let λ be the target slip ratio of the right front wheel. tgt_rl Let λ be the target slip ratio of the left rear wheel. tgt_rr The target slip ratio for the right rear wheel.

[0089] Step S1022d: Determine the wheel speed difference based on the target wheel speed and the actual wheel speed.

[0090] Specifically, the formula for calculating the wheel speed difference of each wheel is as follows:

[0091] Δ v,fl =v fl_ref -v fl

[0092] Δv,fr =v fr_ref -v fr

[0093] Δ v,rl =v rl_ref -v rl

[0094] Δ v,rr =v rr_ref -v rr

[0095] Where, Δ v,fl The left front wheel speed difference (m / s), Δ v,fr The wheel speed difference of the right front wheel (m / s), Δ v,rl The left rear wheel speed difference (m / s), Δ v,rr The speed difference of the right rear wheel is (m / s).

[0096] Optionally, the preset judgment rules include a first judgment rule and a second judgment rule. The first judgment rule determines the slip state of the electric vehicle based on the target slip ratio and the actual slip ratio of each wheel. The second judgment rule determines the slip state of the electric vehicle based on the wheel speed difference of each wheel. Determining the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel, and the preset judgment rules includes: determining the slip state of the electric vehicle as braking slip in response to the target slip ratio and the actual slip ratio of each wheel satisfying the first judgment rule, or determining the slip state of the electric vehicle as braking slip in response to the wheel speed difference of each wheel satisfying the second judgment rule.

[0097] For example, braking slip is considered to have occurred when any of the following criteria are met:

[0098] First criterion: The actual slip ratio λ of a single wheel is greater than the target slip ratio λ. tgt +Slip ratio deviation λ thr When the vehicle speed is low, the deviation setting is larger; when the vehicle speed is high, the deviation setting is smaller. For example, in this case, the slip ratio deviation λ... thr The settings are as follows:

[0099]

[0100] Where v represents the current vehicle speed, v thrsh1 v is the preset first speed threshold. thrsh2 This is the preset second speed threshold.

[0101] Second criterion: The wheel speed difference of a single wheel is greater than the wheel speed difference threshold Δ v,thrWhen the vehicle speed is low, the wheel speed difference threshold is set to a smaller value; when the vehicle speed is high, the wheel speed difference threshold is set to a larger value. In this example, the wheel speed difference threshold is set as follows:

[0102]

[0103] Where v represents the current vehicle speed, v thrsh1 v is the preset first speed threshold. thrsh2 This is the preset second speed threshold.

[0104] If neither of the two judgment rules is met and the driver does not request braking, the slip ratio control is discontinued.

[0105] Optionally, in response to the slip state being braking slip, determining the target single-wheel output braking torque includes: in response to the slip state being braking slip, determining the road surface adhesion coefficient; and determining the target single-wheel output braking torque based on the road surface adhesion coefficient.

[0106] Specifically, the determination of the road surface adhesion coefficient is described in the same way as in step S1021. The target single-wheel output braking torque for each wheel is obtained by multiplying the vertical force of that wheel by the road surface adhesion coefficient.

[0107] It should be noted that the vertical force of a wheel refers to the force acting on the wheel in the direction perpendicular to its direction. It is generated by the supporting force exerted by the ground on the wheel when it contacts the ground. The magnitude of the vertical force depends on the contact area between the wheel and the ground, the magnitude of the wheel's weight, and the reaction force exerted by the ground on the wheel.

[0108] Optionally, in response to the slip state being brake slip, determining the target braking torque limit of the power motor includes: in response to the slip state being brake slip, determining the wheel speed difference; and determining the target braking torque limit of the power motor based on the wheel speed difference.

[0109] Specifically, the determination of wheel speed difference has been described in detail in the above embodiments and will not be repeated here.

[0110] For example, the process for determining the target braking torque limit of the power motor is as follows:

[0111] Taking the rear axle as an example, the anti-lock braking closed-loop control strategy is as follows:

[0112] T t arg et =k P Δ v,R +k I ∫Δ v,R

[0113] Among them, T t arg et The target braking torque limit is expressed in Nm and kJ / m². P k I For proportional-integral control parameters, Δv,R Represents the wheel speed difference, k P and k I Adaptive adjustment is achieved based on straight-line and steering conditions.

[0114] To avoid torque and speed fluctuations caused by frequent reciprocating anti-slip control, the recovery of motor torque during anti-lock braking should be minimized. This can be achieved by adjusting control parameters, specifically:

[0115] When Δ v,R When the value is less than 0 (set value), the shaft is considered to be in a slipping state, and the regenerative braking torque of the motor should be reduced rapidly. At this time, the control parameter k... P and k I It is a negative value.

[0116] When Δ v,R When the value is greater than 0 (set value), the main drive shaft is considered to be in a non-slip state. At this time, the motor regenerative braking torque recovery rate factor b should be determined according to the driving conditions such as straight line / steering to reduce the control parameters, quickly restore the system braking energy, extend the anti-slip control time, and try to avoid the problems of speed fluctuation and deceleration fluctuation caused by the fluctuation of motor regenerative torque.

[0117] Under straight-line braking conditions, the anti-slip control parameter factor b is calculated based on the brake pedal opening α. α Specifically:

[0118]

[0119] Among them, b α This is a brake pedal control parameter factor, ranging from 0 to 1, where α is the current brake pedal opening. thrsh This is the brake pedal opening change threshold, a calibrated value, which can be taken as 20%. When the brake pedal opening exceeds a certain level (α...), the brake pedal opening... thrsh When this occurs, it indicates that the driver has a strong intention to brake, and the target braking torque limit can be increased according to the slip state.

[0120] Under low-speed and high-speed braking conditions, the control parameter factor b v The anti-lock braking system (ABS) increases with vehicle speed and decreases at low speeds to avoid excessive intervention from the ABS at low speeds. Specifically:

[0121]

[0122] Among them, b v Here, v is the vehicle speed control parameter factor, ranging from 0 to 1, where v is the vehicle speed in m / s, v1 and v2 are speed calibration values ​​in m / s, and b is the speed control parameter factor. v,1 b v,2 These are the calibration values ​​for the vehicle speed control parameters.

[0123] Based on the above calculations of control parameter factors for different operating conditions, the final control parameter factor (regenerative braking torque recovery rate factor) b is obtained as follows:

[0124] b = max(b α ,b v )

[0125] The control parameters of the proportional-derivative controller are calculated based on the control parameter factor as follows:

[0126]

[0127]

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0129] This embodiment also provides a vehicle braking anti-skid control system, which is used to implement the above embodiments and preferred embodiments, and will not be repeated as already described. As used below, the term "module" refers to a combination of software and / or hardware that can perform a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0130] Figure 2 This is a structural block diagram of a vehicle braking anti-skid control system 200 according to one embodiment of the present invention, as shown below. Figure 2As shown, taking a vehicle braking anti-skid control system 200 as an example, it includes: an acquisition module 201, used to acquire vehicle driving data and basic data, wherein the driving data includes vehicle speed, acceleration, steering wheel angle, yaw rate and actual wheel speed, and the basic data includes wheelbase and track width; a first determination module 202, used to determine the slip state of the electric vehicle based on the driving data and basic data, wherein the slip state includes braking slip and no slip; a second determination module 203, used to determine the target single-wheel output braking torque in response to the slip state being braking slip; a third determination module 204, used to determine the target braking torque limit of the power motor in response to the slip state being braking slip; and a control module 205, used to control the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0131] Optionally, the first determining module 202 is further configured to: determine the target slip ratio of the wheels based on acceleration; determine the actual slip ratio and wheel speed difference of each wheel based on vehicle speed, steering wheel angle, yaw rate, actual wheel speed and basic data; and determine the slip state of the electric vehicle based on the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel and preset judgment rules.

[0132] Optionally, the first determining module 202 is also used to: determine the reference wheel speed of each wheel based on the vehicle speed, steering wheel angle, yaw rate and basic data; and determine the actual slip ratio of each wheel based on the reference wheel speed and the actual wheel speed of each wheel.

[0133] Optionally, the first determining module 202 is further configured to: determine the reference wheel speed of each wheel based on the vehicle speed, steering wheel angle, yaw rate and basic data; determine the target wheel speed of each wheel based on the target slip ratio and the reference wheel speed of each wheel; and determine the wheel speed difference based on the target wheel speed and the actual wheel speed.

[0134] Optionally, the preset determination rules include a first determination rule and a second determination rule, wherein the first determination rule determines the slip state of the electric vehicle based on the target slip ratio and the actual slip ratio of each wheel, and the second determination rule determines the slip state of the electric vehicle based on the wheel speed difference of each wheel; the first determination module 202 is further configured to: determine the slip state of the electric vehicle as braking slip in response to the target slip ratio and the actual slip ratio of each wheel satisfying the first determination rule, or determine the slip state of the electric vehicle as braking slip in response to the wheel speed difference of each wheel satisfying the second determination rule.

[0135] Optionally, the second determining module 203 is further configured to: determine the road surface adhesion coefficient in response to the slip state being braking slip; and determine the target single-wheel output braking torque based on the road surface adhesion coefficient.

[0136] Optionally, the third determining module 204 is also used to: determine the wheel speed difference in response to the slip state being braking slip; and determine the target braking torque limit of the power motor based on the wheel speed difference.

[0137] Embodiments of the present invention also provide a vehicle, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the vehicle braking anti-skid control method described in any of the above embodiments.

[0138] Optionally, in this embodiment, the processor in the vehicle can be configured to run a computer program to perform the following steps:

[0139] Step S101: Obtain vehicle driving data and basic data.

[0140] Step S102: Determine the slip state of the electric vehicle based on the driving data and basic data.

[0141] Step S103: In response to the slip state being braking slip, determine the target single wheel output braking torque.

[0142] Step S104: In response to the slip state being brake slip, determine the target braking torque limit of the power motor.

[0143] Step S105: Control the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0144] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0145] Embodiments of the present invention also provide a non-volatile storage medium storing a computer program, wherein the computer program is configured to execute the vehicle braking anti-skid control method described in any of the above embodiments when running on a computer or processor.

[0146] Optionally, in this embodiment, the computer program described above may be configured to store a computer program for performing the following steps:

[0147] Step S101: Obtain vehicle driving data and basic data.

[0148] Step S102: Determine the slip state of the electric vehicle based on the driving data and basic data.

[0149] Step S103: In response to the slip state being braking slip, determine the target single wheel output braking torque.

[0150] Step S104: In response to the slip state being brake slip, determine the target braking torque limit of the power motor.

[0151] Step S105: Control the electric vehicle based on the target single-wheel output braking torque and the target braking torque limit.

[0152] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0153] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0154] In the embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of modules can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through interfaces, or indirect couplings or communication connections between modules, and may be electrical or other forms.

[0155] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0156] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0157] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0158] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A vehicle brake slip control method, characterized by, The method is applied to an electric vehicle comprising a power motor, and comprises: obtaining driving data and basic data of the electric vehicle, wherein the driving data comprises vehicle speed, acceleration, steering wheel angle, yaw rate and actual wheel speed, and the basic data comprises wheelbase and track; determining a slip state of the electric vehicle according to the driving data and the basic data, wherein the slip state comprises brake slip and non-slip; in response to the slip state being the brake slip, determining a target single-wheel output brake torque; in response to the slip state being the brake slip, determining a target brake torque limit value of the power motor; controlling the electric vehicle according to the target single-wheel output brake torque and the target brake torque limit value; wherein determining the slip state of the electric vehicle according to the driving data and the basic data comprises: determining a target slip ratio of a wheel according to the acceleration; determining an actual slip ratio and a wheel speed difference of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate, the actual wheel speed and the basic data; and determining the slip state of the electric vehicle according to the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel and a preset determination rule; the preset determination rule comprises a first determination rule and a second determination rule, wherein the first determination rule determines the slip state of the electric vehicle according to the target slip ratio and the actual slip ratio of each wheel, and the second determination rule determines the slip state of the electric vehicle according to the wheel speed difference of each wheel; and determining the slip state of the electric vehicle according to the target slip ratio, the actual slip ratio of each wheel, the wheel speed difference of each wheel and the preset determination rule comprises: in response to the target slip ratio and the actual slip ratio of each wheel satisfying the first determination rule, determining that the slip state of the electric vehicle is the brake slip, or in response to the wheel speed difference of each wheel satisfying the second determination rule, determining that the slip state of the electric vehicle is the brake slip.

2. The vehicle brake slip control method according to claim 1, characterized by, determining the actual slip ratio of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate, the actual wheel speed and the basic data comprises: determining a reference wheel speed of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate and the basic data; determining the actual slip ratio of each wheel according to the reference wheel speed of each wheel and the actual wheel speed of each wheel.

3. The vehicle brake slip control method according to claim 1, characterized by, determining the wheel speed difference of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate, the actual wheel speed and the basic data comprises: determining a reference wheel speed of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate and the basic data; determining a target wheel speed of each wheel according to the target slip ratio and the reference wheel speed of each wheel; determining the wheel speed difference according to the target wheel speed and the actual wheel speed.

4. The vehicle brake slip control method according to claim 1, characterized by, in response to the slip state being the brake slip, determining a target single-wheel output brake torque comprises: determining a road adhesion coefficient in response to the slip state being the brake slip; determining the target single-wheel output brake torque according to the road adhesion coefficient.

5. The vehicle brake slip control method according to claim 1, characterized by, The determining the target brake torque limit value of the power motor in response to the slip state being the brake slip comprises: determining a wheel speed difference in response to the slip state being the brake slip; determining the target brake torque limit value of the power motor according to the wheel speed difference.

6. A vehicle brake slip control system characterized by, comprise: an acquisition module, configured to acquire driving data and basic data of an electric vehicle, wherein the driving data comprises vehicle speed, acceleration, steering wheel angle, yaw rate and actual wheel speed, and the basic data comprises wheelbase and track; a first determination module, configured to determine a slip state of the electric vehicle according to the driving data and the basic data, wherein the slip state comprises brake slip and non-slip; a second determination module, configured to determine a target single-wheel output brake torque in response to the slip state being the brake slip; a third determination module, configured to determine a target brake torque limit value of a power motor in response to the slip state being the brake slip; a control module, configured to control the electric vehicle according to the target single-wheel output brake torque and the target brake torque limit value; The first determination module is further configured to determine a target slip rate of a wheel according to the acceleration, determine an actual slip rate and a wheel speed difference of each wheel according to the vehicle speed, the steering wheel angle, the yaw rate, the actual wheel speed and the basic data, and determine the slip state of the electric vehicle according to the target slip rate, the actual slip rate of each wheel, the wheel speed difference of each wheel and a preset determination rule. The preset determination rule comprises a first determination rule and a second determination rule, wherein the first determination rule determines the slip state of the electric vehicle according to the target slip rate and the actual slip rate of each wheel, and the second determination rule determines the slip state of the electric vehicle according to the wheel speed difference of each wheel. The first determination module is further configured to determine that the slip state of the electric vehicle is the brake slip in response to the target slip rate and the actual slip rate of each wheel satisfying the first determination rule, or determine that the slip state of the electric vehicle is the brake slip in response to the wheel speed difference of each wheel satisfying the second determination rule.

7. A vehicle comprising a memory and a processor, characterized in that The memory stores a computer program, and the processor is configured to execute the computer program to perform the vehicle brake anti-slip control method in any one of claims 1 to 5.

8. A non-volatile storage medium, comprising: The non-volatile storage medium stores a computer program, and the computer program is configured to perform the vehicle brake anti-slip control method in any one of claims 1 to 5 when executed on a computer or a processor.

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