CN117774712A - Vehicle, brake control method thereof, brake control device and storage medium - Google Patents
Vehicle, brake control method thereof, brake control device and storage medium Download PDFInfo
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Abstract
The invention discloses a vehicle, a braking control method, a braking control device and a storage medium, wherein the method comprises the following steps: determining that the electronic hydraulic braking system cannot provide braking assistance, acquiring the slip rate of the driving wheels under the condition that a braking signal is acquired, and adjusting the motor braking moment of the vehicle according to the preset motor braking moment under the condition that the slip rate of the driving wheels exceeds a preset threshold value. According to the braking control method, when the electronic hydraulic braking system fails, braking deceleration generated by motor braking is utilized to the maximum extent, vehicle stability is maintained, and driving safety is improved.
Description
Technical Field
The present invention relates to the field of vehicle technology, and more particularly, to a vehicle brake control method, a vehicle brake control device, a computer-readable storage medium, and a vehicle.
Background
With the development of automobile technology, new energy vehicles and automatic driving vehicles put new demands on braking systems. At present, a conventional hydraulic braking system provides braking assistance through a vacuum booster, so that the force of a driver stepping on a brake pedal can be reduced, and the braking is easier, but the stepping force is directly used as assistance and can be limited by an installation space. In addition, EHBs (Electric Hydraulic Brake, electro-hydraulic brake systems) use servomotors to provide brake assistance, and the brake system is monitored and controlled by an ECU (Electronic Control Unit ) and sensors, although EHBs have many advantages in providing braking performance and driving experience, there are also some potential safety risks such as electronic system failure, power supply failure, internal pressure leakage, sensor failure, and so forth. EHB, unlike conventional hydraulic braking systems, may be sudden, and may have serious consequences if a failure occurs at a critical moment.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, a first object of the present invention is to provide a vehicle brake control method, which can obtain a slip ratio of a driving wheel in real time when an electro-hydraulic brake system cannot provide a brake assistance, and adjust a motor brake torque of a vehicle according to a set motor brake torque when the slip ratio exceeds a set threshold value, so that a brake deceleration generated by braking the motor can be maximized when the electro-hydraulic brake system fails, thereby maintaining the stability of the vehicle and improving the driving safety.
A second object of the present invention is to provide a vehicle brake control device.
A third object of the present invention is to propose a computer readable storage medium.
A fourth object of the present invention is to propose a vehicle.
To achieve the above object, an embodiment of a first aspect of the present invention provides a vehicle brake control method, including: determining that the electro-hydraulic braking system is unable to provide braking assistance; acquiring the slip rate of the driving wheel under the condition that a braking signal is acquired; and under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the motor braking moment of the vehicle according to the preset motor braking moment.
According to the vehicle braking control method provided by the embodiment of the invention, the fact that the electronic hydraulic braking system cannot provide braking assistance is determined, the slip rate of the driving wheels is obtained under the condition that a braking signal is acquired, and the motor braking moment of the vehicle is adjusted according to the preset motor braking moment under the condition that the slip rate of the driving wheels exceeds a preset threshold value. Therefore, when the electronic hydraulic braking system cannot provide braking assistance, the method acquires the slip rate of the driving wheel in real time, and when the slip rate exceeds a set threshold value, the motor braking moment of the vehicle is adjusted according to the set motor braking moment, so that the braking deceleration generated by utilizing motor braking can be maximized when the electronic hydraulic braking system fails, the stability of the vehicle is maintained, and the driving safety is improved.
In addition, the vehicle brake control method according to the above embodiment of the invention may further have the following additional technical features:
according to some embodiments of the invention, in case a braking signal is acquired, the method further comprises: controlling the vehicle according to the available maximum motor braking torque; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, the available maximum motor braking moment is adjusted to be the preset motor braking moment; and controlling the vehicle according to the available maximum motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
According to other embodiments of the present invention, in the case of acquiring a brake signal, the vehicle brake control method further includes: determining a target motor braking torque according to the vehicle speed; controlling the vehicle according to the target motor braking moment; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the target motor braking moment to be the preset motor braking moment; and controlling the vehicle according to the target motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
According to some embodiments of the invention, obtaining a slip ratio of a drive wheel includes: acquiring the wheel speed of the driving wheel and the wheel speed of the non-driving wheel through a brake anti-lock system; acquiring a wheel speed difference between the wheel speed of the non-driving wheel and the wheel speed of the driving wheel; and determining the slip rate of the driving wheel according to the ratio of the absolute value of the wheel speed difference to the wheel speed of the non-driving wheel.
According to some embodiments of the invention, determining that an electro-hydraulic braking system is unable to provide braking assistance includes: the method comprises the steps that parameter data of an electronic hydraulic braking system are not received by a brake anti-lock system; or the parameter data is received at the brake antilock system and the brake boosting condition cannot be satisfied.
According to some embodiments of the invention, the brake boosting condition comprises: the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance value; and/or the failure level of the electro-hydraulic brake system is below a preset level.
According to some embodiments of the invention, the vehicle brake control method further includes: when the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance threshold value, controlling the electronic hydraulic braking system to distribute the motor braking moment and the hydraulic braking moment according to the braking moment; and under the condition that the slip rate of the driving wheel exceeds a preset threshold value, carrying out reduction control on the motor braking torque of the vehicle until the slip rate of the driving wheel does not exceed the preset threshold value.
To achieve the above object, a second aspect of the present invention provides a vehicle brake control device, comprising: the determining module is used for determining that the electronic hydraulic braking system cannot provide braking assistance; the acquisition module is used for acquiring the slip rate of the driving wheel under the condition that the braking signal is acquired; and the control module is used for adjusting the motor braking moment of the vehicle according to the preset motor braking moment under the condition that the slip rate of the driving wheel exceeds the preset threshold value.
According to the vehicle brake control device provided by the embodiment of the invention, the determining module determines that the electronic hydraulic brake system cannot provide brake assistance, the acquiring module acquires the slip rate of the driving wheel under the condition that the brake signal is acquired, and the control module adjusts the motor brake moment of the vehicle according to the preset motor brake moment under the condition that the slip rate of the driving wheel exceeds the preset threshold. Therefore, when the electronic hydraulic braking system cannot provide braking assistance, the device acquires the slip rate of the driving wheel in real time, and when the slip rate exceeds a set threshold value, the motor braking moment of the vehicle is adjusted according to the set motor braking moment, so that the braking deceleration generated by utilizing motor braking can be maximized when the electronic hydraulic braking system fails, the stability of the vehicle is maintained, and the driving safety is improved.
To achieve the above object, a third aspect of the present invention provides a computer-readable storage medium having stored thereon a vehicle brake control program which, when executed by a processor, implements the above-described vehicle brake control method.
The computer readable storage medium of the embodiment of the invention can maximize the braking deceleration generated by utilizing motor braking when the electronic hydraulic braking system fails by executing the vehicle braking control method, maintain the stability of the vehicle and improve the driving safety.
In order to achieve the above object, a fourth aspect of the present invention provides a vehicle, which includes a memory, a processor, and a vehicle brake control program stored in the memory and capable of running on the processor, wherein the processor implements the vehicle brake control method when executing the vehicle brake control program.
According to the vehicle disclosed by the embodiment of the invention, by executing the vehicle brake control method, when the electronic hydraulic brake system fails, the brake deceleration generated by braking by the motor can be maximized, the stability of the vehicle is maintained, and the driving safety is improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a vehicle brake control method according to some embodiments of the invention;
FIG. 2 is a schematic illustration of a vehicle brake control method according to further embodiments of the present invention;
FIG. 3 is a block schematic diagram of a vehicle brake control device according to some embodiments of the present invention;
fig. 4 is a block schematic diagram of a vehicle according to some embodiments of the invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
A vehicle brake control method, a vehicle brake control device, a computer-readable storage medium, and a vehicle according to embodiments of the present invention are described below with reference to the accompanying drawings.
As EHBs begin to be applied on vehicles, security has become a primary concern. Currently, for a vehicle configured with an EHB and an ESC (Electronic Stability Controller, body electronic stability control system), when the EHB assist function fails, the EHB requests the ESC to perform the HBC (Hydraulic Brake Failure Compensation, hydraulic brake fault compensation) function. After the HBC function is activated, when a driver presses a brake pedal, the master cylinder pressure changes, the HBC function recognizes the brake intention of the driver according to the master cylinder pressure change, controls the pressure building pump to work and actively builds the wheel cylinder pressure, and therefore the driver assistance is achieved. At this time, the braking request of the driver is realized by the ESC active pressure building, and the braking full authority under all working conditions is controlled by the ESC, including the braking working condition of the driver, the stability function, the auxiliary function (such as active pressure building) and the like.
However, the ESC adopted by the current vehicle is not popular because of high price, so the main stream is generally configured by ABS (Antilock Brake System, anti-lock braking system) without HBC function, the deceleration generated by stepping on the brake pedal only by the driver when EHB fails is small, the force of stepping on the brake pedal by each user is different or the capability of predicting risk is different, and other auxiliary emergency measures need to be considered because of lack of more effective redundant brake backup. The braking energy recovery of the motor can generate larger braking torque, the motor can be used as auxiliary braking when the EHB power assisting fails, but the motor braking only acts on a driving shaft (a commercial vehicle is a rear axle generally), when the motor braking torque is larger, the ABS function is easy to trigger to activate, and in order to keep the stability of the vehicle, the motor braking is completely withdrawn in the conventional way, but the use experience of a user is easy to be reduced.
Therefore, the application provides a vehicle brake control method, when an electronic hydraulic brake system cannot provide brake assistance, the slip rate of a driving wheel is obtained in real time, when the slip rate exceeds a set threshold value, the motor brake moment of the vehicle is adjusted according to the set motor brake moment, so that the brake deceleration generated by utilizing motor brake can be maximized when the electronic hydraulic brake system fails, the stability of the vehicle is maintained, and the driving safety is improved.
Fig. 1 is a flow chart of a vehicle brake control method according to some embodiments of the invention.
As shown in fig. 1, the vehicle brake control method according to the embodiment of the invention may include the steps of:
s1, determining that the electronic hydraulic brake system cannot provide brake assistance.
Specifically, the electro-hydraulic braking system and the brake anti-lock braking system communicate with each other through a CAN (Controller Area Network ) to transmit data, for example, the electro-hydraulic braking system may send a maximum boosting ability value to the ABS system in real time. When the ABS system does not receive the data sent by the electro-hydraulic brake system or the data received by the ABS system does not meet the requirements, the fact that the electro-hydraulic brake system cannot provide brake assistance can be determined.
S2, under the condition that a braking signal is acquired, the slip rate of the driving wheel is acquired.
Specifically, whether the driver has a braking intention is determined by collecting a change in the opening degree of the brake pedal, or a pressure value is detected by a sensor mounted on the brake pedal, and when the pressure value increases, a collected braking signal is determined, which indicates that the driver is stepping on the brake pedal to brake, and at this time, the slip ratio of the driving wheels can be obtained by the wheel speeds of the front and rear wheels of the vehicle. For example, when the driving wheel is a rear wheel, a wheel speed difference between the wheel speed of the front wheel and the wheel speed of the rear wheel is obtained, and then the slip ratio of the rear wheel is determined according to the ratio of the wheel speed difference to the wheel speed of the front wheel. The slip ratio of the driving wheel may be calculated in various ways, and is not limited thereto.
And S3, under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the motor braking moment of the vehicle according to the preset motor braking moment, wherein the preset threshold value and the preset motor braking moment can be calibrated according to actual conditions. For example, the preset motor braking torque may be determined according to a slip ratio of the driving wheel, different slip ratios corresponding to different preset motor braking torques, and the preset threshold value is smaller than the slip ratio corresponding to when the anti-lock braking system is activated.
Specifically, when the electronic hydraulic braking system fails, if a braking signal is acquired, the need of braking control on wheels is indicated, the slip rate of the driving wheels is acquired, and whether the motor braking moment of the vehicle is braked and adjusted by adopting a preset motor braking moment or not is determined according to the slip rate of the driving wheels. When the slip rate of the driving wheel exceeds a preset threshold, the ABS function is easily activated to enable the motor brake to be completely withdrawn, so that the braking deceleration generated by the motor brake cannot be fully utilized to assist the brake, the brake can be realized only by stepping on a brake pedal by a driver, and at the moment, the whole vehicle controller can override the motor brake moment according to the set motor brake moment to carry out braking adjustment on the motor brake moment of the vehicle; or, the whole vehicle controller is controlled to control the wheels according to a conventional motor braking control strategy, then the slip rate of the driving wheels is obtained in real time in the process of motor braking control of the wheels, the motor braking moment of the driving wheels is adjusted to be the preset motor braking moment under the condition that the slip rate of the driving wheels exceeds a preset threshold value, when the slip rate of the driving wheels is lower than the preset threshold value, the ABS function is not activated, the ABS system does not interfere with motor braking, and the vehicle can be controlled according to the actual motor braking moment. Therefore, when the electronic hydraulic braking system fails, the braking deceleration generated by motor braking can be utilized to the maximum, the stability of the vehicle is maintained, and the driving safety is improved.
The vehicle brake control method of the embodiment of the invention is described in detail below.
In some embodiments of the present invention, in the case of acquiring a brake signal, the method further includes: controlling the vehicle according to the available maximum motor braking torque; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, the available maximum motor braking moment is adjusted to be the preset motor braking moment; and controlling the vehicle according to the available maximum motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
Specifically, when the electronic hydraulic brake system fails, if a brake signal is acquired, the vehicle controller sends a currently available maximum motor brake torque value (available maximum motor brake torque) to the ABS system, and the ABS system takes the maximum motor brake torque value as a motor brake request value and actively sends override control to the whole vehicle controller. The whole vehicle controller firstly carries out braking control on the vehicle according to the available maximum motor braking moment, so that the response speed is high, the energy recovery can be fully utilized, and the ABS system is adopted to request electric braking. In the process that the vehicle controller carries out braking control on the driving wheels according to the available maximum motor braking moment, the slip rate of the driving wheels is obtained in real time, and whether the motor braking moment of the vehicle is braked and adjusted by adopting the preset motor braking moment or not is determined according to the slip rate of the driving wheels. When the slip rate of the driving wheel exceeds a preset threshold, the ABS function is easy to activate, and the available maximum motor braking moment can be adjusted to be the preset motor braking moment at the moment, so that the whole vehicle controller limits the braking moment of the vehicle according to the preset motor braking moment, and the ABS function is prevented from being activated. When the slip rate of the driving wheel does not exceed a preset threshold value, the function of the ABS system is not activated, the ABS system does not interfere with motor braking, and the vehicle can be controlled according to the available maximum motor braking moment at the moment, so that the braking can be performed by fully utilizing the electromechanical braking energy recovery.
In other embodiments of the present invention, in the case of acquiring a brake signal, the vehicle brake control method further includes: determining a target motor braking torque according to the vehicle speed; controlling the vehicle according to the target motor braking moment; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the target motor braking moment to be the preset motor braking moment; and controlling the vehicle according to the target motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
Specifically, when the electronic hydraulic braking system fails, if a braking signal is acquired, a target motor braking moment is determined according to the relation between the vehicle speed and the motor braking moment, and then the vehicle is controlled according to the target motor braking moment. The method comprises the steps of obtaining the current vehicle running speed through an instrument panel on the vehicle at the moment, inquiring a corresponding braking energy recovery MAP table according to the current vehicle running speed, and determining the target motor braking moment. In the process of controlling the vehicle according to the target motor braking moment, the slip rate of the driving wheel is obtained in real time, and when the slip rate of the driving wheel does not exceed a preset threshold value, the function of the ABS system is not activated, the ABS system does not interfere with motor braking, and the vehicle is continuously braked according to the target motor braking moment. When the slip rate of the driving wheel exceeds a preset threshold, the function of the ABS system is easy to activate, the target motor braking moment is adjusted to be the preset motor braking moment, and the vehicle is braked and controlled according to the preset motor braking moment. The motor braking signal is sent by the whole vehicle controller, and the braking deceleration generated by motor braking can be fully utilized by adopting a mode of braking energy recovery MAP (MAP) meter, so that the stability and the safety of the vehicle are improved, the control mode is simple, and the function of an ABS (antilock brake system) is not required to be changed.
In some embodiments of the invention, obtaining the slip ratio of the drive wheel includes: acquiring the wheel speed of the driving wheel and the wheel speed of the non-driving wheel through a brake anti-lock system; acquiring a wheel speed difference between the wheel speed of the non-driving wheel and the wheel speed of the driving wheel; and determining the slip rate of the driving wheel according to the ratio of the absolute value of the wheel speed difference to the wheel speed of the non-driving wheel.
Specifically, the wheel speed of the driving wheel and the wheel speed of the non-driving wheel may be obtained by a brake anti-lock system, wherein the magnitude of the wheel speed is mainly dependent on the road surface state, for example, the road surface is relatively smooth when the vehicle is running in winter, the wheel speed is relatively small, and then the slip ratio of the driving wheel is calculated according to the ratio of the absolute value of the wheel speed difference of the non-driving wheel to the wheel speed of the non-driving wheel. When the vehicle is a commercial vehicle, the front wheel is generally used as a non-driving wheel, and the rear wheel is generally used as a driving wheel, and the slip ratio is a ratio of a wheel speed difference between the wheel speed of the front wheel and the wheel speed of the rear wheel to the wheel speed of the front wheel. When the vehicle is a home vehicle, the rear wheel is generally used as a non-driving wheel, and the front wheel is generally used as a driving wheel, and the slip ratio is a ratio of a wheel speed difference between a wheel speed of the rear wheel and a wheel speed of the front wheel to a wheel speed of the rear wheel.
In some embodiments of the invention, determining that an electro-hydraulic braking system is unable to provide braking assistance includes: the method comprises the steps that parameter data of an electronic hydraulic braking system are not received by a brake anti-lock system; or the parameter data is received at the brake antilock system and the brake boosting condition cannot be satisfied.
Specifically, the electronic hydraulic braking system and the anti-lock braking system are communicated through CAN, data are mutually transmitted, when the anti-lock braking system does not receive parameter data of the electronic hydraulic braking system, the communication between the electronic hydraulic braking system and the anti-lock braking system is abnormal, and at the moment, it CAN be determined that the electronic hydraulic braking system cannot provide braking assistance. Or when the brake anti-lock system receives the parameter data sent by the electronic hydraulic brake system but the parameter data cannot meet the brake assistance condition, the electronic hydraulic brake system is determined to be incapable of providing brake assistance, and the failure of the electronic hydraulic brake system can be determined more accurately.
In some embodiments of the present invention, the brake assist conditions may include: the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance value; and/or the failure level of the electro-hydraulic brake system is below a preset level. The preset power-assisted value and the preset grade can be calibrated according to actual conditions.
Specifically, when the brake assistance value of the electro-hydraulic brake system is greater than a preset assistance value, the electro-hydraulic brake system can provide brake assistance, and the brake assistance value of the electro-hydraulic brake system is smaller than the preset assistance value, which indicates that the electro-hydraulic brake system cannot provide brake assistance. Or when the failure level of the electronic hydraulic brake system is lower than the preset level, the failure of the electronic hydraulic brake system is light and does not affect the braking of the vehicle, so that the braking assistance can be provided, and when the failure level of the electronic hydraulic brake system is higher than the preset level, the failure of the electronic hydraulic brake system is serious and can cause certain influence on the braking of the vehicle, and the braking assistance cannot be provided. Or when the braking assistance value of the electronic hydraulic braking system is larger than the preset assistance value and the failure level of the electronic hydraulic braking system is lower than the preset level, determining that the braking assistance condition is met. The fault levels of the electronic hydraulic brake system are divided into a first level, a second level, a third level, a fourth level, a fifth level and the like according to the sequence from small to large, when the fault level is the first level (such as message loss) or the second level (such as single-way sensor fault), the electronic hydraulic brake system can provide brake assistance, and when the fault level is the fourth level or the fifth level, the electronic hydraulic brake system can not provide brake assistance or consider that parts in the system have problems.
In some embodiments of the present invention, the vehicle brake control method further includes: when the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance threshold value, controlling the electronic hydraulic braking system to distribute the motor braking moment and the hydraulic braking moment according to the braking moment; and under the condition that the slip rate of the driving wheel exceeds a preset threshold value, carrying out reduction control on the motor braking torque of the vehicle until the slip rate of the driving wheel does not exceed the preset threshold value. The preset power-assisted threshold can be calibrated according to actual conditions.
Specifically, the electronic hydraulic braking system sends a braking assistance value to the braking anti-lock braking system in real time through CAN communication, when the braking assistance value is larger than a preset assistance threshold value, the electronic hydraulic braking system is indicated to be capable of providing braking assistance, the electronic hydraulic braking system is not in a situation of assistance failure, at the moment, the electronic hydraulic braking system is controlled to distribute motor braking moment and hydraulic braking moment according to braking moment, and electric braking energy is fully utilized for braking. Because road conditions are complex and changeable, in order to ensure driving safety, when the wheels are braked and controlled in a mode of combining hydraulic braking and motor braking, the slip rate of the driving wheels is obtained in real time, when the slip rate is detected to exceed a preset threshold value, the ABS function is easily excited to be activated, so that the motor braking is completely withdrawn, braking deceleration generated by the motor braking cannot be fully utilized to assist braking, motor braking torque of the vehicle can be reduced and controlled at the moment until the slip rate of the driving wheels does not exceed the preset threshold value, so that the motor braking cannot be completely withdrawn, the motor braking torque can be regulated when the slip rate of the driving wheels just exceeds the preset threshold value, and the vehicle stability is improved.
In some embodiments, when the slip rate is detected to exceed the preset threshold, the slip rate of the driving wheel still exceeds the preset threshold when the motor braking torque of the vehicle is controlled to be reduced until the motor braking torque is reduced to 0, and at this time, the hydraulic braking torque of the vehicle is controlled to be reduced until the slip rate of the driving wheel does not exceed the preset threshold.
For example, as shown in fig. 2, the EHB of the electro-hydraulic braking system communicates with the ABS of the brake anti-lock braking system through CAN, the EHB transmits its own braking assistance value and failure level to the ABS, and after receiving the braking assistance value and failure level transmitted by the EHB, the ABS determines whether to execute the eDTC (Electrification of Drag Torque Control, torque control) function, that is, whether to determine, according to the slip ratio of the driving wheel, to perform braking adjustment on the motor braking torque of the vehicle by using the preset motor braking torque. For example, when the EHB is normal or generally malfunctioning (does not affect the provision of brake assistance), activation is controlled in accordance with the slip ratio of the drive wheels; when the EHB is lost or has a critical fault, i.e., it is determined that the EHB is not providing brake assistance, it is indicated that the EHB is not transmitting motor brake requests and hydraulic brake requests, and the eDTC function is activated in response to the brake switch signal. When a vehicle VCU (Vehicle Control Unit, vehicle controller) receives a brake pedal switch signal, motor braking torque is requested according to driver input or preset MAP or ABS torque limits, and braking control is performed on wheels. Meanwhile, the ABS acquires the front wheel speed and the rear wheel speed, and calculates the slip rate of the driving wheel and the motor braking torque limit (preset motor braking torque) in real time according to the front wheel speed and the rear wheel speed. When the slip rate of the driving wheel exceeds a preset threshold, the ABS sends a motor braking torque limit value to the VCU for override control, so that the VCU carries out braking control on the wheels according to the motor braking torque limit value; and when the slip rate of the driving wheels does not exceed a preset threshold, requesting motor braking torque according to the input of a driver or the preset MAP or ABS torque limit, and performing braking control on the wheels.
Or determining that the EHB cannot provide braking assistance, when the vehicle VCU receives a brake pedal switch signal, sending a currently available maximum motor braking torque value (available maximum motor braking torque) to the ABS, and sending the available maximum motor braking torque serving as a motor braking request value to the VCU by the ABS for override control so that the VCU can brake the wheels according to the available maximum motor braking torque. Meanwhile, the ABS acquires the front wheel speed and the rear wheel speed, and calculates the slip rate of the driving wheel and the motor braking torque limit (preset motor braking torque) in real time according to the front wheel speed and the rear wheel speed. When the slip rate of the driving wheel exceeds a preset threshold, the ABS sends a motor braking torque limit value to the VCU for override control, so that the VCU carries out braking control on the wheels according to the motor braking torque limit value; when the slip rate of the driving wheel does not exceed the preset threshold, the ABS takes the available maximum motor braking moment as a motor braking request value so that the VCU can continuously brake and control the wheels according to the available maximum motor braking moment.
Therefore, the method and the device automatically identify the power failure working condition of the electronic hydraulic brake system through signal interaction and judgment of the brake anti-lock system and the electronic hydraulic brake system when the power failure of the electronic hydraulic brake system and the motor braking are needed to make an emergency, then calculate the slip rate of the driving wheel through the brake anti-lock system, control the motor in real time to send out the maximum braking moment, not only keep the stability of the vehicle, but also fully utilize the braking deceleration generated during the motor braking, and improve the safety of the vehicle.
In summary, according to the vehicle brake control method of the embodiment of the invention, it is determined that the electro-hydraulic brake system cannot provide brake assistance, the slip ratio of the driving wheels is obtained under the condition that the brake signal is collected, and the motor brake torque of the vehicle is adjusted according to the preset motor brake torque under the condition that the slip ratio of the driving wheels exceeds the preset threshold. Therefore, when the electronic hydraulic braking system cannot provide braking assistance, the method acquires the slip rate of the driving wheel in real time, and when the slip rate exceeds a set threshold value, the motor braking moment of the vehicle is adjusted according to the set motor braking moment, so that the braking deceleration generated by utilizing motor braking can be maximized when the electronic hydraulic braking system fails, the stability of the vehicle is maintained, and the driving safety is improved.
Corresponding to the embodiment, the invention also provides a vehicle brake control device.
As shown in fig. 3, the vehicle brake control apparatus 100 of the embodiment of the invention may include: a determination module 110, an acquisition module 120, and a control module 130.
The determination module 110 is configured to determine that the electro-hydraulic braking system is unable to provide braking assistance. The acquisition module 120 is configured to acquire a slip ratio of the driving wheel in a case where a brake signal is acquired. The control module 130 is configured to adjust a motor braking torque of the vehicle according to a preset motor braking torque if a slip ratio of the driving wheels exceeds a preset threshold.
In some embodiments of the present invention, the control module 130 is further configured to control the vehicle based on the available maximum motor braking torque in the event that a braking signal is acquired; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, the available maximum motor braking moment is adjusted to be the preset motor braking moment; and controlling the vehicle according to the available maximum motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
In other embodiments of the present invention, the control module 130 is further configured to determine a target motor braking torque based on the vehicle speed in the event that a braking signal is acquired; controlling the vehicle according to the target motor braking moment; under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the target motor braking moment to be the preset motor braking moment; and controlling the vehicle according to the target motor braking moment under the condition that the slip rate of the driving wheels does not exceed the preset threshold value.
In some embodiments of the present invention, the acquisition module 120 acquires a slip ratio of the driving wheel, specifically for: acquiring the wheel speed of the driving wheel and the wheel speed of the non-driving wheel through a brake anti-lock system; acquiring a wheel speed difference between the wheel speed of the non-driving wheel and the wheel speed of the driving wheel; and determining the slip rate of the driving wheel according to the ratio of the absolute value of the wheel speed difference to the wheel speed of the non-driving wheel.
In some embodiments of the present invention, the determination module 110 determines that the electro-hydraulic brake system is unable to provide brake assistance, particularly for: the method comprises the steps that parameter data of an electronic hydraulic braking system are not received by a brake anti-lock system; or the parameter data is received at the brake antilock system and the brake boosting condition cannot be satisfied.
In some embodiments of the invention, the brake assist conditions include: the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance value; and/or the failure level of the electro-hydraulic brake system is below a preset level.
In some embodiments of the present invention, the control module 130 is further configured to control the electro-hydraulic brake system to allocate the motor braking torque and the hydraulic braking torque according to the braking torque when the braking assistance value of the electro-hydraulic brake system is greater than a preset assistance threshold; and under the condition that the slip rate of the driving wheel exceeds a preset threshold value, carrying out reduction control on the motor braking torque of the vehicle until the slip rate of the driving wheel does not exceed the preset threshold value.
It should be noted that, for details not disclosed in the vehicle brake control device according to the embodiment of the present invention, please refer to details disclosed in the vehicle brake control method according to the embodiment of the present invention, and details are not described again.
According to the vehicle brake control device provided by the embodiment of the invention, the determining module determines that the electronic hydraulic brake system cannot provide brake assistance, the acquiring module acquires the slip rate of the driving wheel under the condition that the brake signal is acquired, and the control module adjusts the motor brake moment of the vehicle according to the preset motor brake moment under the condition that the slip rate of the driving wheel exceeds the preset threshold. Therefore, when the electronic hydraulic braking system cannot provide braking assistance, the device acquires the slip rate of the driving wheel in real time, and when the slip rate exceeds a set threshold value, the motor braking moment of the vehicle is adjusted according to the set motor braking moment, so that the braking deceleration generated by utilizing motor braking can be maximized when the electronic hydraulic braking system fails, the stability of the vehicle is maintained, and the driving safety is improved.
The present invention also proposes a computer-readable storage medium corresponding to the above-described embodiments.
The computer-readable storage medium of the present invention has stored thereon a vehicle brake control program that, when executed by a processor, implements the vehicle brake control method described above.
The computer readable storage medium of the embodiment of the invention can maximize the braking deceleration generated by utilizing motor braking when the electronic hydraulic braking system fails by executing the vehicle braking control method, maintain the stability of the vehicle and improve the driving safety.
Corresponding to the embodiment, the invention also provides a vehicle.
As shown in fig. 4, the vehicle 200 according to the embodiment of the invention includes a memory 210, a processor 220, and a vehicle brake control program stored in the memory 210 and capable of running on the processor 220, and when the processor 220 executes the vehicle brake control program, the above-mentioned vehicle brake control method is implemented.
According to the vehicle disclosed by the embodiment of the invention, by executing the vehicle brake control method, when the electronic hydraulic brake system fails, the brake deceleration generated by braking by the motor can be maximized, the stability of the vehicle is maintained, and the driving safety is improved.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, for example, may be considered as a ordered listing of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. A vehicle brake control method, characterized by comprising:
determining that the electro-hydraulic braking system is unable to provide braking assistance;
acquiring the slip rate of the driving wheel under the condition that a braking signal is acquired;
and under the condition that the slip rate of the driving wheel exceeds a preset threshold value, adjusting the motor braking moment of the vehicle according to the preset motor braking moment.
2. The control method according to claim 1, characterized in that in the case where the brake signal is acquired, the method further comprises:
controlling the vehicle according to the available maximum motor braking torque;
under the condition that the slip rate of the driving wheel exceeds a preset threshold value, the available maximum motor braking moment is adjusted to be the preset motor braking moment;
and under the condition that the slip rate of the driving wheel does not exceed a preset threshold value, controlling the vehicle according to the available maximum motor braking moment.
3. The control method according to claim 1, characterized in that in the case where the brake signal is acquired, the method further comprises:
determining a target motor braking torque according to the vehicle speed;
controlling the vehicle according to the target motor braking moment;
under the condition that the slip rate of the driving wheel exceeds the preset threshold value, adjusting the target motor braking moment to be the preset motor braking moment;
and controlling the vehicle according to the target motor braking moment under the condition that the slip rate of the driving wheel does not exceed the preset threshold value.
4. The control method according to claim 1, characterized in that acquiring the slip ratio of the drive wheel includes:
acquiring the wheel speed of the driving wheel and the wheel speed of the non-driving wheel through a brake anti-lock system;
acquiring a wheel speed difference between the wheel speed of the non-driving wheel and the wheel speed of the driving wheel;
and determining the slip rate of the driving wheel according to the ratio of the absolute value of the wheel speed difference to the wheel speed of the non-driving wheel.
5. The control method of claim 1, wherein determining that the electro-hydraulic brake system is unable to provide brake assistance comprises:
the method comprises the steps that parameter data of the electronic hydraulic braking system are not received by a brake anti-lock system; or alternatively
The parameter data is received at the anti-lock brake system and the brake boosting condition cannot be satisfied.
6. The control method according to claim 5, characterized in that the brake assist condition includes:
the braking assistance value of the electronic hydraulic braking system is larger than a preset assistance value; and/or
The failure level of the electro-hydraulic brake system is lower than a preset level.
7. The control method according to any one of claims 1 to 6, characterized by further comprising:
controlling the electronic hydraulic brake system to distribute motor braking moment and hydraulic braking moment according to braking moment under the condition that the braking assistance value of the electronic hydraulic brake system is larger than a preset assistance threshold value;
and under the condition that the slip rate of the driving wheel exceeds the preset threshold value, carrying out reduction control on the motor braking moment of the vehicle until the slip rate of the driving wheel does not exceed the preset threshold value.
8. A vehicle brake control apparatus characterized by comprising:
the determining module is used for determining that the electronic hydraulic braking system cannot provide braking assistance;
the acquisition module is used for acquiring the slip rate of the driving wheel under the condition that the braking signal is acquired;
and the control module is used for adjusting the motor braking moment of the vehicle according to the preset motor braking moment under the condition that the slip rate of the driving wheel exceeds a preset threshold value.
9. A computer-readable storage medium, characterized in that a vehicle brake control program is stored thereon, which when executed by a processor implements the vehicle brake control method according to any one of claims 1 to 7.
10. A vehicle comprising a memory, a processor and a vehicle brake control program stored on the memory and operable on the processor, the processor implementing the vehicle brake control method of any one of claims 1-7 when executing the vehicle brake control program.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410095853.1A CN117774712A (en) | 2024-01-23 | 2024-01-23 | Vehicle, brake control method thereof, brake control device and storage medium |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410095853.1A CN117774712A (en) | 2024-01-23 | 2024-01-23 | Vehicle, brake control method thereof, brake control device and storage medium |
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| CN117774712A true CN117774712A (en) | 2024-03-29 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118651197A (en) * | 2024-07-16 | 2024-09-17 | 比亚迪股份有限公司 | Vehicle braking control method, device, medium and vehicle |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118651197A (en) * | 2024-07-16 | 2024-09-17 | 比亚迪股份有限公司 | Vehicle braking control method, device, medium and vehicle |
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