Wheel anti-lock function control system and method

Abstract

The application belongs to the technical field of vehicle control, and particularly relates to a wheel anti-lock function control system and method; the system comprises a signal receiving module and a wheel anti-lock function control module, wherein the signal receiving module is used for receiving wheel speed information of four wheels, a brake pedal signal and an output signal of a vehicle height sensor; the wheel anti-lock function control module controls a driving system and a braking system according to information received by the signal receiving module and information transmitted by a vehicle ECU, and further controls braking forces of the four wheels of the vehicle; the application monitors changes in relative positions of the four wheels relative to a vehicle body through four vehicle height sensors, identifies whether the current wheels are passing through a speed bump or other obstacles, avoids the problem of loss of braking force of the whole vehicle caused by false triggering of the wheel anti-lock function due to false identification of the wheel lock state.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control technology, specifically relating to a wheel anti-lock braking system and method. Background Technology

[0002] With the increasing popularity of new energy vehicles, almost all vehicles equipped with electric motors are equipped with regenerative braking. However, a phenomenon is becoming more and more apparent: when driving a new energy vehicle and applying the brakes to go over a speed bump, the vehicle will lurch forward momentarily upon landing, resulting in a momentary loss of deceleration. This can cause panic for the driver and, in some cases, even lead to an accident.

[0003] The reason for the instantaneous loss of deceleration in a vehicle is as follows: New energy vehicles have a regenerative braking function. When the vehicle goes over a speed bump, the wheels will be airborne for a short time. During this instant, the wheels will rotate at a different speed because there is no rolling resistance. If the wheel going over the speed bump is the drive wheel, the wheel speed will increase instantaneously. The braking system will detect that the wheel speed is greater than the vehicle speed and will determine that the wheel may lock up. To prevent the wheel from locking up, the vehicle will restore the wheel speed to the same as the vehicle speed by clearing the regenerative braking force of the motor and reducing the hydraulic braking force of the locked wheel. When the wheel returns to the ground after passing the speed bump, the motor braking force has been cleared to zero and the hydraulic braking force has also been reduced. Due to the reduction in braking force, the vehicle will momentarily lose some deceleration.

[0004] To solve this problem, it is necessary to accurately identify whether the abnormal wheel speed is due to hitting a speed bump, and then take corresponding measures to address the anti-lock braking system to prevent an unexpected reduction in braking force. Currently, no solution for this problem is known. Summary of the Invention

[0005] To overcome the above problems, the present invention provides a wheel anti-lock braking system and method; it is a wheel anti-lock braking control strategy to prevent the loss of deceleration when the vehicle goes over speed bumps. It uses four vehicle height sensors to monitor the changes in the relative position of the wheels to the vehicle body, and identifies whether the current wheels are going over speed bumps or other obstacles, so as to avoid the problem of the whole vehicle losing braking force due to the incorrect identification of wheel lock-up state and the incorrect triggering of wheel anti-lock braking function.

[0006] An anti-lock braking system (ABS) includes a signal receiving module and an ABS control module. The signal receiving module receives wheel speed information of the four wheels, brake pedal signals, and output signals from the vehicle height sensor. The ABS control module controls the drive system and braking system based on the information received by the signal receiving module and the information transmitted by the vehicle ECU, thereby controlling the braking force of the four wheels of the vehicle.

[0007] A method for controlling wheel anti-lock braking function includes the following:

[0008] Step 1: The anti-lock braking system (ABS) module estimates the vehicle speed based on the wheel speeds of the four wheels received by the signal receiving module, and calculates the slip ratio of the four wheels. When the slip ratio exceeds the limit required by regulations, it is determined that the wheel has locked up. To prevent wheel lock-up and ensure the adhesion between the wheel and the ground, anti-lock braking treatment is required. The ABS control module controls the braking force of the wheel to keep the slip ratio within the limit, thereby preventing wheel lock-up.

[0009] Step two: To avoid misjudging wheel lock-up, the anti-lock braking system (ABS) first determines whether the driver has pressed the brake pedal based on the brake pedal information received by the signal receiving module. If it is confirmed that the driver has pressed the brake pedal, the output signal value of the vehicle height sensor within A seconds before the slip ratio exceeds the limit needs to be read to determine whether the relative position change between the wheel and the vehicle body is continuous. If it is not continuous, it is determined that the wheel has hit an obstacle and the wheel is briefly suspended in the air. At this time, the ABS does not perform anti-lock braking control on the wheel to reduce braking force; that is, the ABS does not participate in braking and strictly executes braking according to the driver's braking force requirements.

[0010] If the relative position between a wheel and the vehicle body changes continuously when the slip ratio exceeds the limit, the anti-lock braking system (ABS) module will determine that the wheel has locked up and will need to perform anti-lock braking on the wheel.

[0011] The anti-lock braking function control module performs the following anti-lock braking process on the wheels:

[0012] The anti-lock braking system (ABS) module determines whether the vehicle's ECU has requested regenerative braking force from the vehicle's electric motor. If so, the ABS module controls the braking system to reset the vehicle's electric motor's braking force to zero. After clearing the regenerative braking force, the ABS module does not participate in braking and applies hydraulic braking force according to the driver's needs. Simultaneously, the ABS module releases the hydraulic braking force on the locked wheels, using the slip ratio limit as the control target. After depressurization, the ABS module does not participate in braking and continues to apply the driver's required braking force until the wheel slip ratio returns to within the limit.

[0013] In step two, the slip ratio is the ratio of the difference between the wheel speed and the vehicle speed to the wheel speed.

[0014] The beneficial effects of this invention are:

[0015] This invention uses four vehicle height sensors to monitor changes in the relative position of the wheels to the vehicle body, identifying whether the wheels are currently passing over speed bumps or other obstacles. If the vehicle is passing over speed bumps or other obstacles, then anti-lock braking control will not be applied to the wheels. This avoids the problem of incorrectly triggering the anti-lock braking function due to incorrect identification of wheel lock-up, which could lead to loss of vehicle braking force, failure of the vehicle to decelerate as required by the driver, causing driver panic, or even a collision. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to embodiments. In the description of the present invention, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0017] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0018] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0019] Example 1

[0020] An anti-lock braking system (ABS) includes a signal receiving module and an ABS control module. The signal receiving module receives wheel speed information of the four wheels, brake pedal signals, and output signals from the vehicle height sensor. The ABS control module controls the drive system and braking system based on the information received by the signal receiving module and the information transmitted by the vehicle ECU, thereby controlling the braking force of the four wheels of the vehicle.

[0021] A method for controlling wheel anti-lock braking function includes the following:

[0022] Step 1: The anti-lock braking system (ABS) module estimates the vehicle speed based on the wheel speeds of the four wheels received by the signal receiving module, and calculates the slip ratio of the four wheels. When the slip ratio exceeds the limit required by regulations, it is determined that the wheel has locked up. To prevent wheel lock-up and ensure the adhesion between the wheel and the ground, anti-lock braking treatment is required. The ABS control module controls the braking force of the wheel to keep the slip ratio within the limit, thereby preventing wheel lock-up.

[0023] Step two: To avoid misjudging wheel lock-up, the anti-lock braking system (ABS) first determines whether the driver has pressed the brake pedal based on the brake pedal information received by the signal receiving module. If the driver has pressed the brake pedal, the output signal value of the vehicle height sensor within A seconds before the slip ratio exceeds the limit is read to determine whether the relative position change between the wheel and the vehicle body is continuous. If the relative position change between the wheel and the vehicle body corresponding to the wheel with the slip ratio exceeding the limit is not continuous, it is determined that the wheel has hit an obstacle and the wheel is briefly suspended in the air. At this time, the ABS does not perform anti-lock braking control to reduce the braking force of the wheel; that is, the ABS does not participate in braking and strictly executes braking according to the driver's braking force requirements.

[0024] If the relative position between a wheel and the vehicle body changes continuously when the slip ratio exceeds the limit, the anti-lock braking system (ABS) module will determine that the wheel has locked up and will need to perform anti-lock braking on the wheel.

[0025] The anti-lock braking function control module performs the following anti-lock braking process on the wheels:

[0026] Step 1: The anti-lock braking system (ABS) module determines whether the vehicle's ECU has requested regenerative braking force from the vehicle's electric motor. If so, the ABS module controls the braking system to clear the vehicle's electric motor's braking force to zero, preventing interference from the electric motor's power on the ABS control. After clearing the regenerative braking force, the ABS module does not participate in braking and applies hydraulic braking according to the driver's required braking force. Simultaneously, the ABS module depressurizes the hydraulic braking force on the locked wheels, using the slip ratio limit as the control target. After depressurization, the ABS module does not participate in braking and continues to apply the driver's required braking force until the wheel slip ratio returns to within the limit.

[0027] In step two, the slip ratio is the ratio of the difference between the wheel speed and the vehicle speed to the wheel speed.

[0028] Example 2

[0029] The system receives the wheel speeds of the vehicle's four wheels and calculates the vehicle speed based on these speeds; it receives the driver's brake pedal opening and determines the required braking force based on this information; the system receives data from the vehicle's four height sensors, which measure the relative position changes between the vehicle body and the wheels; the system interacts with the drive and braking systems based on the received information to control the braking force of the vehicle's four wheels; and the system notifies the driver via the instrument panel when a function is activated.

[0030] The specific control strategy for anti-lock braking system (ABS) to prevent loss of deceleration when a vehicle goes over speed bumps:

[0031] First, the system estimates the vehicle speed by receiving the wheel speeds of the four wheels based on the vehicle's drive type and overall vehicle parameters. The estimated vehicle speed is then compared with the wheel speeds of the four wheels. The ratio of the difference between the wheel speed and the vehicle speed to the wheel speed is the wheel slip ratio. When the slip ratio exceeds the limit, it is determined that the wheel has locked up. To prevent wheel lock-up and ensure the adhesion between the wheel and the ground, anti-lock treatment is required for the wheel.

[0032] To avoid misjudging wheel lock-up, the system first checks if the driver has applied the brake pedal. If so, it reads the real-time changes in the positions of the four wheels and their corresponding body sections, calculating the values ​​within A seconds before the slip ratio exceeds the limit. If the rate of change of the relative position between the wheel and the body is not continuous, it indicates that the wheel has collided with an obstacle, resulting in a brief period of suspension. In this case, the anti-lock braking system should not be applied to that wheel to reduce braking force; instead, the system must strictly adhere to the driver's braking force requirements.

[0033] During the control process, real-time monitoring is required to monitor the entire system in a continuous cycle.

[0034] If the rate of change of the relative position between the wheel with the slip ratio exceeding the limit and the vehicle body is continuous, then the wheel is considered to have locked up and needs to be addressed. First, determine if the vehicle motor's regenerative braking force has been requested. If so, reset the vehicle motor's braking force to zero to avoid interference with the wheel anti-lock control. After clearing the vehicle motor's regenerative braking force, apply hydraulic braking force according to the driver's required braking force. Simultaneously, using the slip ratio as the control target, depressurize the hydraulic braking force of the locked wheel. After depressurization, continue to apply the driver's required braking force until the wheel slip ratio returns to within the limit, and then exit the function.

[0035] The preferred embodiments of the present invention have been described in detail above. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0036] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0037] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A control method of wheel anti-lock function, which is implemented by a wheel anti-lock function control system, the wheel anti-lock function control system comprising a signal receiving module and a wheel anti-lock function control module, wherein the signal receiving module is configured to receive wheel speed information of four wheels, a brake pedal signal, and an output signal of a vehicle height sensor, and the wheel anti-lock function control module is configured to control a drive system and a brake system according to information received by the signal receiving module and information transmitted by a vehicle ECU, and further control brake forces of the four wheels of the vehicle; characterized in that The control method comprises the following contents: Step one, the wheel anti-lock function control module estimates the vehicle speed according to the wheel speeds of the four wheels received by the signal receiving module, and calculates the slip rates of the four wheels, and determines that a wheel lock condition occurs when the slip rate exceeds a limit value required by regulations, and the wheel anti-lock function control module needs to perform anti-lock processing on the wheel to avoid wheel lock and ensure the adhesion between the wheel and the ground; wherein the wheel anti-lock function control module controls the wheel brake force to control the slip rate of the wheel within the limit value, thereby performing anti-lock processing on the wheel; Step two, in order to avoid misjudgment of the wheel lock condition, the wheel anti-lock function control module first determines whether the driver has stepped on the brake pedal according to the brake pedal information received by the signal receiving module, and if it is confirmed that the driver has stepped on the brake pedal at this time, the output signal value of the vehicle height sensor within A seconds before the slip rate exceeds the limit value is read to determine whether the relative position change between the wheel and the vehicle body is continuous, and if not, it is determined that the wheel has hit an obstacle and the wheel is in a short-time suspended condition; at this time, the wheel anti-lock function control module does not perform wheel anti-lock control to reduce the brake force of the wheel, that is, the wheel anti-lock function control module does not participate in braking, and strictly executes braking according to the brake force demand of the driver; If the relative position change between the wheel whose slip rate exceeds the limit value and the vehicle body is continuous, the wheel anti-lock function control module determines that the wheel has a wheel lock condition and needs to perform anti-lock processing on the wheel; The wheel anti-lock function control module performs anti-lock processing on the wheel as follows: The wheel anti-lock function control module determines whether the vehicle ECU has requested the recovery brake force of the vehicle motor, and controls the brake system to clear the brake force of the vehicle motor if the request is made; after the recovery brake force of the vehicle motor is cleared, the wheel anti-lock function control module does not participate in braking and performs hydraulic braking according to the brake force demand of the driver; at the same time, the wheel anti-lock function control module controls the hydraulic brake force of the locked wheel to be released with the slip rate limit value as the control target, and after the release, the wheel anti-lock function control module does not participate in braking and continues to execute the brake force demand of the driver until the slip rate of the wheel returns to within the limit value.

2. The control method of wheel anti-lock function according to claim 1, characterized in that, The slip rate in step two is the ratio of the difference between the wheel speed and the vehicle speed to the wheel speed.

3. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the control method of the wheel anti-lock function according to any one of claims 1-2 when executing the program.

4. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program causes a processor to implement the control method of the wheel anti-lock function according to any one of claims 1 to 2 when executed by the processor.