CN118457524A - Control method of brake-by-wire system, vehicle controller and vehicle - Google Patents
Control method of brake-by-wire system, vehicle controller and vehicle Download PDFInfo
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- CN118457524A CN118457524A CN202410595040.9A CN202410595040A CN118457524A CN 118457524 A CN118457524 A CN 118457524A CN 202410595040 A CN202410595040 A CN 202410595040A CN 118457524 A CN118457524 A CN 118457524A
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000035939 shock Effects 0.000 claims abstract description 32
- 239000006096 absorbing agent Substances 0.000 claims abstract description 31
- 238000012360 testing method Methods 0.000 claims description 20
- 230000000994 depressogenic effect Effects 0.000 claims description 11
- 230000000694 effects Effects 0.000 abstract description 7
- 230000000875 corresponding effect Effects 0.000 description 16
- 238000003825 pressing Methods 0.000 description 11
- 230000033001 locomotion Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 239000000725 suspension Substances 0.000 description 7
- 230000008859 change Effects 0.000 description 5
- 238000011981 development test Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 238000013016 damping Methods 0.000 description 3
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- 238000006243 chemical reaction Methods 0.000 description 2
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/17—Using electrical or electronic regulation means to control braking
- B60T8/1755—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve
- B60T8/17555—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve specially adapted for enhancing driver or passenger comfort, e.g. soft intervention or pre-actuation strategies
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/17—Using electrical or electronic regulation means to control braking
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- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
Abstract
The invention discloses a control method of a brake-by-wire system, a vehicle controller and a vehicle, and belongs to the technical field of vehicles, wherein the control method of the brake-by-wire system is characterized in that after a driver presses a brake pedal, the stroke of the brake pedal pressed is obtained, the vehicle activates a comfortable braking mode due to smaller stroke, the stroke of the brake pedal pressed is substituted into the comfortable braking relation curve to obtain the current braking force of the vehicle in the comfortable braking mode, then the pitch angle of the vehicle is calculated according to the current braking force, finally the heights of shock absorbers of front wheels and rear wheels of the vehicle are respectively adjusted according to the pitch angle, the pitch angle of the vehicle is reduced or eliminated, the brake and the shock absorbers cooperatively operate to solve the problem of vehicle shrugging, the brake force control of brake-by-wire is more accurate and rapid, the effect of comfortable braking can be achieved while driving more severely, and the comfort of passengers in driving is greatly improved.
Description
Technical Field
The present invention relates to the field of vehicle technologies, and in particular, to a brake-by-wire system control method, a vehicle controller, and a vehicle.
Background
An automotive braking system refers to a series of specialized devices that apply a certain force to the wheels of an automobile, thereby effecting a degree of forced braking thereof. The brake-by-wire system is an electronic control brake system, and the biggest difference between the brake-by-wire system and the traditional brake system is that the transmission medium of the brake-by-wire system is an electronic signal and is electronically controlled, and no physical connection exists between the pedal and the brake system. The internal structure of the linear control system is simple, the volume is light, the reaction force is sensitive, and the linear control system is in a relatively stable state during operation.
Brake comfort refers to the feeling of the driver caused by the change in longitudinal dynamics of the vehicle when the vehicle is braked. At present, when a vehicle equipped with a brake-by-wire system is braked and braked by braking, because the reaction of the brake-by-wire system is sensitive, the situation that the vehicle tows due to overlarge braking force easily occurs after a driver presses a brake pedal, and most of the towering energy is absorbed by a suspension system, but the driver can feel pitching of the vehicle, and the comfort is poor.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a control method of the brake-by-wire system, wherein the brake and the shock absorber cooperatively work to solve the problem of vehicle shrugging, the brake force control of the brake-by-wire system is more accurate and rapid, the effect of comfortable braking can be achieved while the driver is driven more violently, and the comfort of drivers and passengers in driving is greatly improved.
The invention also provides a vehicle controller and a vehicle for executing the control method of the brake-by-wire system.
The control method of the linear control brake system according to the first aspect of the embodiment of the invention comprises the following steps:
acquiring the stroke of the brake pedal when the brake pedal is stepped on, and judging whether the vehicle activates a comfortable braking mode according to the stroke;
When the vehicle is determined to activate a comfortable braking mode, the current braking force of the vehicle is obtained according to the travel and comfortable braking relation curve, wherein the comfortable braking relation curve is constructed by preset data of the vehicle and is used for representing the relation between the travel of the brake pedal which is stepped on and the braking force of the vehicle;
And obtaining a pitch angle of the vehicle according to the current braking force, and respectively adjusting the heights of a front wheel damper and a rear wheel damper of the vehicle according to the pitch angle.
The control method of the brake-by-wire system has at least the following beneficial effects: after a driver steps on a brake pedal, the stroke of the brake pedal is obtained, the vehicle activates a comfortable braking mode because the stroke is smaller, the stroke of the brake pedal is substituted into a comfortable braking relation curve, the current braking force of the vehicle in the comfortable braking mode is obtained, then the pitch angle of the vehicle is calculated according to the current braking force, finally the heights of a front wheel shock absorber and a rear wheel shock absorber of the vehicle are respectively adjusted according to the pitch angle, the pitch angle of the vehicle is reduced or eliminated, the brake and the shock absorber cooperatively operate to solve the problem that the vehicle tows, the braking force control of the brake-by-wire is more accurate and rapid, the effect of comfortable braking can be achieved while the vehicle is driven more violently, and the comfort of a driver in the running process is greatly improved.
According to some embodiments of the invention, the comfort braking relationship is constructed from preset data of the vehicle, comprising:
Performing a test on the condition that a stroke of a brake pedal is depressed, and calibrating a braking force of the vehicle according to the test;
and establishing a coordinate system by taking the stroke of the brake pedal as an abscissa and the braking force of the vehicle as an ordinate, and drawing the comfortable braking relation curve in the coordinate system.
According to some embodiments of the invention, the calibrating the braking force of the vehicle according to the test includes:
And setting the braking force of the vehicle in the test, and recording the corresponding braking force of the vehicle when the vehicle stops at a safe distance.
According to some embodiments of the invention, the obtaining the pitch angle of the vehicle according to the current braking force includes:
calculating the current deceleration of the vehicle according to the current braking force;
And obtaining a pitch angle according to the current deceleration and a corresponding relation, wherein the corresponding relation is constructed by preset data of the vehicle and is used for representing the relation between the deceleration and the pitch angle.
According to some embodiments of the invention, the obtaining the current braking force of the vehicle according to the travel and comfort braking relation comprises:
and respectively adjusting the braking force of the front wheel brake and the braking force of the rear wheel brake of the vehicle according to the current braking force, so that the braking force of the front wheel brake after adjustment is larger than the braking force of the rear wheel brake.
According to some embodiments of the invention, the adjusting the heights of the front wheel damper and the rear wheel damper of the vehicle according to the pitch angle includes:
And adjusting the height of the front wheel shock absorber and the height of the rear wheel shock absorber according to the pitch angle, so that the adjusted height of the front wheel shock absorber is larger than the height of the rear wheel shock absorber.
According to some embodiments of the invention, the determining whether the vehicle activates the comfort braking mode according to the journey includes:
acquiring the current speed of the vehicle, and judging whether the current speed is greater than a preset speed threshold;
When the current vehicle speed is determined to be greater than the preset vehicle speed threshold value, acquiring the current road surface condition of the vehicle, and judging whether the current road surface condition is normal or not;
When the current road surface condition is determined to be normal, acquiring the current gradient of the vehicle, and judging whether the current gradient is smaller than a preset gradient threshold value or not;
when the current gradient is determined to be smaller than the preset gradient threshold value, judging whether the stroke is smaller than a preset stroke threshold value or not;
When it is determined that the travel is less than the preset travel threshold, the vehicle activates a comfort braking mode.
According to some embodiments of the invention, the brake-by-wire system control method further comprises:
And when the vehicle is not activated in the comfortable braking mode, obtaining the conventional braking force of the vehicle according to the travel and conventional braking relation curve, wherein the conventional braking relation curve is constructed by preset data of the vehicle and is used for representing the relation between the travel of the brake pedal which is depressed and the braking force of the vehicle.
A vehicle controller according to a second aspect of an embodiment of the present invention includes:
A processor;
And a memory storing instructions that, when executed by the processor, perform the brake-by-wire system control method described in the embodiment of the first aspect described above.
The vehicle controller according to the embodiment of the invention has at least the following beneficial effects: the brake and the shock absorber cooperatively work to solve the problem that the vehicle tows, the brake force control of the brake-by-wire is more accurate and rapid, the effect of comfortable braking can be achieved while the vehicle is driven more violently, and the comfort of drivers and passengers in the driving process is greatly improved.
A vehicle according to a third aspect of an embodiment of the present invention includes the vehicle controller according to the embodiment of the second aspect described above.
The vehicle adopts the vehicle controller to execute the control method of the brake-by-wire system, the brake and the shock absorber cooperatively work to solve the problem of vehicle shrugging, the brake force control of the brake-by-wire system is more accurate and rapid, the effect of comfortable braking can be achieved while the vehicle is driven more violently, and the comfort of drivers and passengers in running is greatly improved.
Because the vehicle adopts all the technical schemes of the vehicle controller in the above embodiments, the vehicle controller at least has all the beneficial effects brought by the technical schemes in the above embodiments, and the description thereof is omitted.
Additional features and advantages of the invention will be set forth 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 method of controlling a brake-by-wire system according to an embodiment of the present invention;
FIG. 2 is a flow chart of determining whether a vehicle activates a comfort braking mode in an embodiment of the present invention;
FIG. 3 is a flow chart of a method for establishing a comfort braking relationship in an embodiment of the present invention;
FIG. 4 is a flow chart of obtaining a pitch angle of a vehicle in an embodiment 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 only and are not to be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms front, rear, upper, lower, axial, circumferential, etc. indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, plural means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and the above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, it should be noted that terms such as arrangement, installation, connection, etc. should be construed broadly, and those skilled in the art may reasonably determine the specific meaning of the foregoing terms in the present invention in combination with the specific content of the technical solution.
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which it is apparent that the embodiments described below are some, but not all embodiments of the invention.
As automobiles go into thousands of households, the driving comfort of the vehicles is becoming increasingly more of a consumer concern. Most of the vehicles in the current market are not provided with a comfortable braking mode, and when the vehicles are braked and braked, most of energy is absorbed by a suspension system, but a driver can feel pitching movement of the vehicles, so that driving comfort is poor.
Although some vehicle suspension systems are equipped with an automatic tuning and uninterrupted shock absorption control system Continuous Damping Control, abbreviated CDC. The microcomputer in the CDC system sends instructions to the suspension after operation and analysis according to signals sent by the sensor and control modes given by a driver, and the suspension can change rigidity and damping coefficient of the suspension according to the instructions given by the microcomputer, so that the vehicle body keeps good stability in the running process, and vibration response of the vehicle body is controlled within an allowable range. The CDC system determines the vehicle running state from data of sensors such as a body acceleration sensor, a wheel acceleration sensor, and a lateral acceleration sensor on the vehicle, and calculates the vehicle running state by the central control unit ECU. And the ECU sends out corresponding instructions to a CDC control valve on the shock absorber, and controls the opening degree of the valve to provide damping suitable for the current state.
While some vehicles are equipped with a comfortable braking mode, all commercial vehicles are hydraulically braked and in conventional CDC systems the shock absorber and brake are controlled separately and are difficult to work with the pitching motion produced by the deceleration braking. In future brake-by-wire system application, the cooperative control of the shock absorber and the brake can be realized through the domain controller, and the shock absorber and the brake are simultaneously controlled in the transverse direction and the longitudinal direction, so that the driving comfort is greatly improved.
The brake-by-wire system is different from the traditional chassis hydraulic power assisting system, the controllers which are respectively and independently controlled are integrated in a domain controller, the domain controller integrates the functional application layer software of a suspension system, a braking system and a steering system, the four wheel ends are provided with independent brake execution units and shock absorber execution units, communication is established with the domain controller, and through signal transmission, the motor movement of the wheel end can apply braking force to a brake and the motor can control the valve body in the shock absorber to realize reciprocating movement of a piston so as to change the height of the shock absorber.
Based on the above, the embodiment of the invention provides the control method of the brake-by-wire system, compared with hydraulic control, the brake force control of the brake-by-wire system is more accurate and quicker, the effect of comfortable braking can be achieved while driving more violently, and the comfort of drivers and passengers in driving is greatly improved.
A brake-by-wire system control method according to an embodiment of the first aspect of the present invention, which is applicable to a vehicle, will be described with reference to fig. 1 to 4, and the brake-by-wire system control method will be described below by way of specific examples.
Referring to fig. 1, a brake-by-wire system control method according to an embodiment of the first aspect of the present invention includes the following steps.
Step S100, obtaining the stroke of the brake pedal when the brake pedal is stepped on, and judging whether the vehicle activates a comfortable braking mode according to the stroke;
Step S200, when the vehicle is determined to activate a comfortable braking mode, the current braking force of the vehicle is obtained according to a travel and comfortable braking relation curve, wherein the comfortable braking relation curve is constructed by preset data of the vehicle and is used for representing the relation between the travel of the brake pedal which is stepped on and the braking force of the vehicle;
and step S300, obtaining a pitch angle of the vehicle according to the current braking force, and respectively adjusting the heights of a front wheel damper and a rear wheel damper of the vehicle according to the pitch angle.
In step S100, the brake pedal is, as the name implies, a power-limiting pedal, i.e., a pedal of a running brake, which is used for deceleration parking. The stroke of the driver pressing the brake pedal is positively correlated with the magnitude of the brake pressure, and the larger the stroke of the driver pressing the brake pedal is, the larger the braking force generated by the brake system is.
The principle of the comfortable braking mode is that braking force is reduced on the premise that the vehicle is braked, pitching motion of the vehicle is reduced or eliminated by adjusting the height of the shock absorber, if the comfortable braking mode is activated under the condition that emergency braking is required by a driver, braking distance is prolonged, and safety risks exist, therefore, the stroke of the driver for stepping on the brake pedal is identified before the comfortable braking mode is activated, and if the stroke of the driver for stepping on the brake pedal is lower than a preset stroke threshold value, the vehicle is proved not to be in an emergency braking state, and the vehicle can activate the comfortable braking mode.
In step S200, after the comfortable braking mode is activated, a comfortable braking relation curve is established through preset data of the vehicle, and the preset data is obtained by performing a real vehicle test on the vehicle in a pre-development test stage and calibrating according to a test result.
In this embodiment, the preset data is obtained by changing the stroke of the driver pressing the brake pedal and setting the braking force of the vehicle according to the stroke during the real vehicle test, so that the vehicle is braked within a safe distance, and the corresponding relationship between the stroke of the driver pressing the brake pedal and the braking force of the vehicle, which meets the safety requirements, is calibrated.
According to the preset data, a comfortable braking relation curve between the stroke of the brake pedal and the braking force of the vehicle can be drawn, so that the current braking force of the vehicle can be obtained by substituting the stroke of the brake pedal into the comfortable braking relation curve.
In step S300, the braking force is associated with the pitch angle of the vehicle, and the greater the braking force, the greater the pitch angle of the vehicle is, so the current braking force obtained in step S200 is generally smaller than the conventional braking force in the conventional state of the vehicle, which can help to reduce the pitch angle of the vehicle, and obtain the corresponding pitch angle according to the current braking force, and then adjust the height of each shock absorber of the vehicle according to the pitch angle, wherein the height adjustment amplitude of the plurality of shock absorbers is smaller, and the pitch motion of the vehicle can be greatly reduced, and if the pitch angle is smaller, the pitch motion of the vehicle can be eliminated through the steps above, thereby improving the comfort of the driver and the passengers in the vehicle.
Referring to fig. 1, the method for controlling a brake-by-wire system according to the embodiment of the first aspect of the present invention further includes the following steps.
Step S400, when it is determined that the vehicle does not activate the comfortable braking mode, obtaining a normal braking force of the vehicle according to a travel and normal braking relation curve, wherein the normal braking relation curve is constructed by preset data of the vehicle and is used for representing a relation between a travel of a brake pedal being depressed and the braking force of the vehicle.
In this embodiment, the preset data is to change the stroke of the driver pressing the brake pedal and set the braking force of the vehicle according to the stroke during the real vehicle test, so that the vehicle is braked within a safe distance, and the braking distance is smaller than the braking distance in the comfortable braking mode, so that the corresponding relationship between the stroke of the driver pressing the brake pedal and the braking force of the vehicle, which meets the safety requirements, is calibrated, and the preset data is obtained.
According to the preset data, a conventional braking relation curve of the stroke of the driver for pressing the brake pedal and the braking force of the vehicle can be drawn, so that the conventional braking force of the vehicle can be obtained by substituting the stroke of the brake pedal into the conventional braking relation curve.
When the comfortable braking mode is not activated, the stroke of the driver pressing the brake pedal is substituted into the conventional braking relation curve, so that the vehicle obtains the conventional braking force, and the vehicle is ensured to be braked in a shorter distance.
Referring to fig. 2, step S100, which determines whether the vehicle activates the comfort brake mode according to the journey, further includes the following steps.
Step S110, obtaining the current speed of the vehicle, and judging whether the current speed is greater than a preset speed threshold;
Step S120, when the current vehicle speed is determined to be greater than a preset vehicle speed threshold value, acquiring the current road surface condition of the vehicle, and judging whether the current road surface condition is normal or not;
step S130, when the current road surface condition is determined to be normal, acquiring the current gradient of the vehicle, and judging whether the current gradient is smaller than a preset gradient threshold value;
Step S140, when the current gradient is determined to be smaller than a preset gradient threshold value, judging whether the stroke is smaller than the preset stroke threshold value or not;
in step S150, when the determined travel is less than the preset travel threshold, the vehicle activates a comfort braking mode.
In step S110, the current vehicle speed may be acquired by a sensor of the vehicle itself, specifically, the wheel speed of the wheel rotation of the vehicle is acquired by the sensor, and the current vehicle speed of the vehicle is calculated by the wheel speed and the radius of the wheel.
The preset vehicle speed threshold can be obtained through a real vehicle test in a vehicle early development test stage, after a comfortable braking mode is activated, the braking force of the vehicle is reduced, the braking distance of the vehicle is prolonged, and when the vehicle speed of the vehicle is smaller, the vehicle cannot be braked and collides in the process of running in a small distance, so that the preset vehicle speed threshold is set, and the safety of running in a low speed and a small distance of the vehicle is ensured.
In step S120, when the current speed of the vehicle exceeds the preset speed threshold, it is necessary to detect the road surface condition where the vehicle is located, and at present, the laser radar of the vehicle may be used to obtain the flatness information of the road surface where the vehicle is running, so as to determine whether the vehicle is on a flat road surface, so as to avoid activating a comfortable braking mode when the vehicle is on a road surface condition such as a pothole road surface, a wet road surface, a curved road surface, etc., and further avoid occurrence of a safety accident due to insufficient braking force of the vehicle, so that the vehicle activates the comfortable braking mode only in a normal road surface condition of the flat road surface, and improve the safety of the vehicle.
In step S130, after the vehicle is in a normal road condition, the road gradient where the vehicle is located needs to be detected, and whether the current gradient is lower than a preset gradient threshold value or not can be determined by measuring the current gradient of the vehicle through a gradient sensor of the vehicle itself.
In step S140, when the current gradient of the vehicle is less than the preset gradient threshold, it is required to determine whether the stroke of the brake pedal being depressed is less than the preset stroke threshold, and the stroke of the brake pedal being depressed can be measured by a displacement sensor in the brake system.
The preset travel threshold value can be used for carrying out an emergency braking test on the vehicle in a development test stage of the front stage of the vehicle, and the travel of the driver for stepping on the brake pedal to move during emergency braking is obtained, so that the preset travel threshold value is obtained.
When the vehicle is in normal running, if the stroke of the driver pressing the brake pedal is larger than or equal to a preset stroke threshold value, the driver is proved to expect emergency braking, so that the braking force of the vehicle is prevented from being reduced due to the fact that the vehicle activates a comfortable braking mode.
In step S150, after the above conditions are satisfied, the vehicle activates the comfort braking mode.
Referring to fig. 3, a comfortable braking relationship is constructed from preset data of a vehicle in step S200, including the following steps.
Step S210, testing under the condition of the stroke of the brake pedal being stepped on, and calibrating the braking force of the vehicle according to the test;
In step S220, a coordinate system is established with the stroke of the brake pedal being depressed as the abscissa and the braking force of the vehicle as the ordinate, and a comfortable braking relation curve is drawn in the coordinate system.
In step S210, a real vehicle test is performed on the vehicle in a development test stage in the early stage of the vehicle, the stroke of the driver pressing the brake pedal is fixed, different braking forces are set for the braking system to verify the braking distances of the vehicle corresponding to the different braking forces, a proper braking force is selected, and the braking force corresponding to the stroke of the brake pedal pressed is further calibrated.
In step S220, a coordinate system is established with the stroke of the brake pedal being depressed as the abscissa and the braking force of the vehicle as the ordinate, and the vehicle development test phase is scaled to the stroke of different brake pedals being depressed and the corresponding braking force are sequentially filled into the coordinate system to form a plurality of points, and the plurality of points are sequentially connected to a stroke vertical braking relation curve.
Step S210, the step of calibrating the braking force of the vehicle according to the test includes the following steps.
Step S211, a braking force of the vehicle is set, and a braking force corresponding to the braking of the vehicle at the safe distance is recorded.
In the actual vehicle test process, the stroke of the driver for pressing the brake pedal is fixed, then the braking force is set, and the braking distance of the vehicle is checked. The magnitude of the braking force is changed until the braking distance of the vehicle is equal to the safe distance, and then the braking force is recorded as the braking force corresponding to the stroke of the comfortable braking relation curve when the brake pedal is depressed.
Step 200, obtaining the current braking force of the vehicle according to the travel and comfortable braking relation curve, and further comprising the following steps.
In step S230, the braking force of the front wheel brake and the braking force of the rear wheel brake of the vehicle are respectively adjusted according to the current braking force, so that the adjusted braking force of the front wheel brake is greater than the braking force of the rear wheel brake.
In general, the braking force of a plurality of wheels of a vehicle will be different according to the ground state of the wheels, and the braking force of the wheels is also related to different driving situations of the vehicle such as turning, rolling, pitching, and the like, so that the brake of each wheel of the vehicle needs to be individually adjusted.
Since the front wheels of the vehicle are subjected to a large force during braking and the front wheels of the vehicle are responsible for steering the vehicle, it is necessary to adjust the braking force of the front wheel brakes to be greater than the braking force of the rear wheel brakes in order to ensure safe braking of the vehicle after the comfort braking mode is activated.
Referring to fig. 4, step S300 of obtaining a pitch angle of the vehicle from the current braking force includes the following steps.
Step S310, calculating the current deceleration of the vehicle according to the current braking force;
Step S320, obtaining a pitch angle according to the current deceleration and the corresponding relation, wherein the corresponding relation is constructed by preset data of the vehicle and is used for representing the relation between the deceleration and the pitch angle.
In step S310, the vehicle braking force is positively correlated with the deceleration, specifically, the deceleration is equal to the braking force divided by the vehicle mass, so the current deceleration of the vehicle can be calculated by dividing the current braking force by the vehicle mass of the vehicle.
In step S320, the preset data of the vehicle may change the deceleration of the vehicle during the real vehicle test and calibrate the deceleration of the vehicle and the pitch angle of the vehicle according to the measured pitch angle of the vehicle to obtain the preset data.
According to preset data, a corresponding relation between the deceleration of the vehicle and the pitch angle of the vehicle can be established, and after the vehicle activates a comfortable braking mode, the pitch angle can be calculated by substituting the current deceleration of the vehicle into the corresponding relation, so that the pitch angle of the vehicle can be accurately calculated, and the heights of a plurality of shock absorbers of the vehicle can be accurately adjusted.
Step S300, respectively adjusting the heights of a front wheel damper and a rear wheel damper of the vehicle according to the pitch angle, and further comprising the following steps.
Step S330, adjusting the height of the front wheel damper and the height of the rear wheel damper according to the pitch angle, so that the height of the front wheel damper after adjustment is larger than the height of the rear wheel damper.
In the braking process of the vehicle, the head of the vehicle can incline downwards, the tail of the vehicle can incline upwards, after the comfortable braking mode is activated, the height of the shock absorber of the front wheel of the vehicle is generally required to be adjusted to be higher than that of the shock absorber of the rear wheel of the vehicle, and the shock absorber of the front wheel lifts the head of the vehicle, so that the pitch angle of the vehicle is reduced or eliminated, and the comfort of drivers and passengers in the vehicle is further improved.
In some embodiments, the comfort braking mode should be exited when the vehicle speed is reduced to 0 km/h; when the vehicle is in a parking state, the comfortable braking mode should restore the braking force to the pressure required by the driver, so that the vehicle cannot slip.
In some embodiments, when the comfort braking mode is activated, the driver continues to deeply depress the brake pedal, and when the brake force increment and pedal speed reach above a threshold value, the threshold value will depend on the specific calibration result, and the comfort braking mode will exit to resume the magnitude of driver demand pressure.
In some embodiments, when the comfort brake mode is activated, the driver releases the brake pedal and the comfort brake mode will exit to the armed state.
In some embodiments, the comfort braking mode is not activated during an emergency braking state, i.e. a braking pressure exceeding 50bar or a deceleration exceeding 5 m/s.
In some embodiments, the comfort brake mode activation hold time should not exceed 3 seconds, which may be adjustable. If the vehicle speed is not reduced to 0km/h after the activation time of the comfortable braking mode exceeds 3s, the vehicle is in an under braking state, and the comfortable braking mode is exited and the pressure is restored to the pressure required by the driver until the vehicle stops.
In some embodiments, the comfort braking mode is considered a safety protection function, which protects the driver from misstep on the pedal after a collision, coma or frightening, so that the function is automatically turned on by default.
An embodiment of a second aspect of the present invention provides a vehicle controller including: a processor; and a memory storing instructions that, when executed by the processor, perform the brake-by-wire system control method as in the above embodiment.
The processor and memory in the vehicle controller may be connected by a bus, for example. The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. The memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk memory, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the control processor, which may be connected to the controller via a network.
The non-transitory software programs and instructions required to implement the control methods of the above embodiments are stored in the memory, and when executed by the processor, the control methods of the above embodiments are executed, and the above steps S100 to S400, S110 to S150, S210 to S230, and S310 to S330 are executed.
The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
An embodiment of a third aspect of the present invention provides a vehicle comprising the vehicle controller of the above embodiment. The vehicle may be a private car such as a sedan, SUV, MPV, or a pick-up. The vehicle may also be an operator vehicle such as a minibus, bus, minivan or large trailer, etc. The vehicle can be an oil vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, the vehicle can be a hybrid vehicle or a pure electric vehicle.
The vehicle adopts the vehicle controller to execute the control method, the brake and the shock absorber cooperatively work to solve the problem of vehicle shrugging, the brake force control of the brake-by-wire is more accurate and rapid, the effect of comfortable braking can be achieved while the vehicle is driven more violently, and the comfort of drivers and passengers in the running process is greatly improved.
Because the vehicle adopts all the technical schemes of the vehicle controller in the above embodiments, the vehicle controller at least has all the beneficial effects brought by the technical schemes in the above embodiments, and the description thereof is omitted.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of one of ordinary skill in the art.
Claims (10)
1. A method of controlling a brake-by-wire system, comprising:
acquiring the stroke of the brake pedal when the brake pedal is stepped on, and judging whether the vehicle activates a comfortable braking mode according to the stroke;
When the vehicle is determined to activate a comfortable braking mode, the current braking force of the vehicle is obtained according to the travel and comfortable braking relation curve, wherein the comfortable braking relation curve is constructed by preset data of the vehicle and is used for representing the relation between the travel of the brake pedal which is stepped on and the braking force of the vehicle;
And obtaining a pitch angle of the vehicle according to the current braking force, and respectively adjusting the heights of a front wheel damper and a rear wheel damper of the vehicle according to the pitch angle.
2. The brake-by-wire system control method according to claim 1, characterized in that the comfort braking relationship is constructed from preset data of the vehicle, comprising:
Performing a test on the condition that a stroke of a brake pedal is depressed, and calibrating a braking force of the vehicle according to the test;
and establishing a coordinate system by taking the stroke of the brake pedal as an abscissa and the braking force of the vehicle as an ordinate, and drawing the comfortable braking relation curve in the coordinate system.
3. The brake-by-wire system control method according to claim 2, wherein the determining the braking force of the vehicle according to the test includes:
And setting the braking force of the vehicle in the test, and recording the corresponding braking force of the vehicle when the vehicle stops at a safe distance.
4. The brake-by-wire system control method according to claim 1, characterized in that the obtaining the pitch angle of the vehicle from the current braking force includes:
calculating the current deceleration of the vehicle according to the current braking force;
And obtaining a pitch angle according to the current deceleration and a corresponding relation, wherein the corresponding relation is constructed by preset data of the vehicle and is used for representing the relation between the deceleration and the pitch angle.
5. The brake-by-wire system control method according to claim 1, wherein the obtaining the current braking force of the vehicle from the stroke-to-comfortable braking relationship curve includes:
and respectively adjusting the braking force of the front wheel brake and the braking force of the rear wheel brake of the vehicle according to the current braking force, so that the braking force of the front wheel brake after adjustment is larger than the braking force of the rear wheel brake.
6. The brake-by-wire system control method according to claim 1, wherein the adjusting the heights of the front wheel damper and the rear wheel damper of the vehicle, respectively, according to the pitch angle, comprises:
And adjusting the height of the front wheel shock absorber and the height of the rear wheel shock absorber according to the pitch angle, so that the adjusted height of the front wheel shock absorber is larger than the height of the rear wheel shock absorber.
7. The brake-by-wire system control method according to claim 1, wherein the determining whether the vehicle activates the comfort brake mode according to the stroke includes:
acquiring the current speed of the vehicle, and judging whether the current speed is greater than a preset speed threshold;
When the current vehicle speed is determined to be greater than the preset vehicle speed threshold value, acquiring the current road surface condition of the vehicle, and judging whether the current road surface condition is normal or not;
When the current road surface condition is determined to be normal, acquiring the current gradient of the vehicle, and judging whether the current gradient is smaller than a preset gradient threshold value or not;
when the current gradient is determined to be smaller than the preset gradient threshold value, judging whether the stroke is smaller than a preset stroke threshold value or not;
When it is determined that the travel is less than the preset travel threshold, the vehicle activates a comfort braking mode.
8. The brake-by-wire system control method according to claim 1, characterized in that the brake-by-wire system control method further comprises:
And when the vehicle is not activated in the comfortable braking mode, obtaining the conventional braking force of the vehicle according to the travel and conventional braking relation curve, wherein the conventional braking relation curve is constructed by preset data of the vehicle and is used for representing the relation between the travel of the brake pedal which is depressed and the braking force of the vehicle.
9. A vehicle controller, characterized by comprising:
A processor;
A memory storing instructions that, when executed by the processor, perform the brake-by-wire system control method of any one of claims 1 to 8.
10. A vehicle comprising the vehicle controller of claim 9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410595040.9A CN118457524A (en) | 2024-05-14 | 2024-05-14 | Control method of brake-by-wire system, vehicle controller and vehicle |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410595040.9A CN118457524A (en) | 2024-05-14 | 2024-05-14 | Control method of brake-by-wire system, vehicle controller and vehicle |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119142306A (en) * | 2024-11-19 | 2024-12-17 | 上海同驭汽车科技有限公司 | Comfortable braking control method, system and readable medium |
| CN119142307A (en) * | 2024-11-19 | 2024-12-17 | 上海同驭汽车科技有限公司 | Comfortable parking control method, equipment, medium and product |
-
2024
- 2024-05-14 CN CN202410595040.9A patent/CN118457524A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119142306A (en) * | 2024-11-19 | 2024-12-17 | 上海同驭汽车科技有限公司 | Comfortable braking control method, system and readable medium |
| CN119142307A (en) * | 2024-11-19 | 2024-12-17 | 上海同驭汽车科技有限公司 | Comfortable parking control method, equipment, medium and product |
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