CN111348023A - Vehicle and braking method and device thereof - Google Patents
Vehicle and braking method and device thereof Download PDFInfo
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- CN111348023A CN111348023A CN201811584255.1A CN201811584255A CN111348023A CN 111348023 A CN111348023 A CN 111348023A CN 201811584255 A CN201811584255 A CN 201811584255A CN 111348023 A CN111348023 A CN 111348023A
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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
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/58—Combined or convertible systems
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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
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61H—BRAKES OR OTHER RETARDING DEVICES SPECIALLY ADAPTED FOR RAIL VEHICLES; ARRANGEMENT OR DISPOSITION THEREOF IN RAIL VEHICLES
- B61H11/00—Applications or arrangements of braking or retarding apparatus not otherwise provided for; Combinations of apparatus of different kinds or types
- B61H11/14—Combinations of different types of brakes, e.g. brake blocks acting on wheel-rim combined with disc brakes
Abstract
The invention provides a vehicle and a braking method and a braking device thereof, wherein the method comprises the following steps: acquiring vehicle state information, and generating a braking request of a vehicle according to the vehicle state information, wherein the vehicle state information comprises the current load, the level, the TCU activation number and the vehicle grouping of the vehicle; and controlling the vehicle to perform electric braking according to the braking request, and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process. Therefore, the method controls the vehicle to electrically brake in the braking process, reduces the abrasion to a braking system, makes the vehicle more stable in the braking process, reduces the noise generated by braking, and improves the comfort of a user for driving the vehicle.
Description
Technical Field
The invention relates to the technical field of vehicle control, in particular to a vehicle and a braking method and device thereof.
Background
At present, the rail vehicle usually adopts a hybrid braking mode during braking, namely, the electric braking and the mechanical braking jointly act on the vehicle to provide the required braking force for the vehicle.
However, the applicant finds that when braking is performed by the above braking method, the mechanical braking may cause abrasion to devices in the braking system, which reduces the service life of the vehicle, and the mechanical braking may generate large impact to the vehicle, which causes the vehicle to shake and the like, which reduces the comfort of the user for driving the vehicle.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
To this end, a first object of the invention is to propose a braking method of a vehicle. The method controls the vehicle to carry out electric braking in the braking process, and mechanical braking is not adopted in the braking process, so that the abrasion of a braking system in the braking process is reduced, the vehicle is more stable in the braking process, the noise generated by braking is reduced, and the comfort of a user in driving and riding the vehicle is improved.
A second object of the invention is to propose a braking device for a vehicle.
A third object of the invention is to propose a vehicle.
A fourth object of the invention is to propose a traction controller.
A fifth object of the present invention is to propose a computer-readable storage medium.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a braking method for a vehicle, including the steps of:
acquiring vehicle state information, and generating a braking request of a vehicle according to the vehicle state information, wherein the vehicle state information comprises the current load, the level, the TCU activation number and the vehicle grouping of the vehicle;
and controlling the vehicle to perform electric braking according to the braking request, and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process.
In addition, according to the braking method of the vehicle of the above embodiment of the present invention, the following additional technical features may be further provided:
in one embodiment of the present invention, the braking method of a vehicle further includes: when the vehicle needs to be parked, the vehicle is controlled to apply mechanical brake to assist the parking of the vehicle.
In one embodiment of the present invention, controlling a vehicle to perform electric braking according to a braking request, and determining whether to end the electric braking according to a current vehicle speed of the vehicle during the electric braking includes: extracting braking torque of the vehicle from a braking request, and electrically braking the vehicle by using the braking torque; in the electric braking process, acquiring a target speed of the vehicle for triggering the electric braking to exit; judging whether the current speed of the vehicle is reduced to the target speed; and if the current vehicle speed is decelerated to the target vehicle speed, controlling the vehicle to exit the electric brake and unloading the torque of the electric brake.
In one embodiment of the present invention, obtaining a target vehicle speed of a vehicle triggering exit of an electric brake further includes: in the electric braking process, whether the current speed of the vehicle is reduced to a preset speed is judged, and if the current speed of the vehicle is reduced to the preset speed, a target speed of the vehicle for triggering the electric braking to exit is obtained in real time.
In one embodiment of the invention, acquiring the target vehicle speed of the vehicle triggering the electric brake to exit comprises the following steps: acquiring the whole vehicle weight, the tire radius, the torque unloading rate and the gear ratio of the vehicle; acquiring the maximum deceleration of the vehicle according to the maximum torque of the vehicle; acquiring torque unloading time required by the vehicle to finish torque unloading according to the vehicle weight, the tire radius, the absolute value of the maximum deceleration, the torque unloading rate and the gear ratio; acquiring deceleration of the vehicle in the process of finishing torque unloading according to the maximum deceleration and a preset equivalent acceleration coefficient; and acquiring the target vehicle speed according to the torque unloading time and the deceleration in the torque unloading process.
In one embodiment of the present invention, after obtaining the torque unloading time required for the vehicle to complete the torque unloading, the method further includes: and correcting the torque unloading time by using the torque filtering delay time of the vehicle.
In one embodiment of the present invention, after the torque unloading time and the deceleration during the torque unloading process, the method further comprises: acquiring the current gradient and the current ground adhesion coefficient of the vehicle; acquiring ramp deceleration according to the current gradient; acquiring deceleration caused by friction according to the current ground adhesion coefficient; and correcting the deceleration during the unloading process by using the slope deceleration and the deceleration caused by the friction force.
According to the vehicle braking method, the vehicle state information is obtained firstly, the vehicle braking request is generated according to the vehicle state information, then the vehicle is controlled to perform electric braking according to the braking request, and whether the electric braking is finished or not is judged according to the current vehicle speed of the vehicle in the electric braking process. Therefore, in the vehicle braking process, the purpose of vehicle braking can be achieved through electric braking, mechanical braking is not adopted in the braking process, abrasion to a braking system in the braking process is reduced, the vehicle is more stable in the braking process, noise generated by braking is reduced, and comfort of a user in driving and riding the vehicle is improved. Further, the method can calculate the braking torque currently required by the vehicle according to the state information of the vehicle so that the vehicle can output the torque for braking, and after the vehicle is braked, the electric braking torque is unloaded when the vehicle speed is reduced to the target vehicle speed for quitting the electric braking of the vehicle, so that the electric braking force is reduced to zero at the same time when the vehicle speed is reduced to zero, and the vehicle is prevented from rolling backwards.
In order to achieve the above object, an embodiment of a second aspect of the present invention provides a brake apparatus for a vehicle, including:
the generating module is used for acquiring vehicle state information and generating a braking request of the vehicle according to the vehicle state information, wherein the vehicle state information comprises the current load, the level, the TCU activation number and the vehicle code of the vehicle;
and the brake control module is used for controlling the vehicle to perform electric braking according to the braking request and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process.
The parking control device of the embodiment of the invention firstly obtains the vehicle state information, generates the braking request of the vehicle according to the vehicle state information, then controls the vehicle to perform electric braking according to the braking request, and judges whether to finish the electric braking according to the current vehicle speed of the vehicle in the electric braking process. Therefore, in the vehicle braking process, the purpose of vehicle braking can be achieved through electric braking, mechanical braking is not adopted in the braking process, abrasion to a braking system in the braking process is reduced, the vehicle is more stable in the braking process, noise generated by braking is reduced, and comfort of a user in driving and riding the vehicle is improved. Further, the device can calculate the braking torque currently required by the vehicle according to the state information of the vehicle so that the vehicle can output the torque for braking, and after the vehicle is braked, the electric braking torque is unloaded when the vehicle speed is reduced to the target vehicle speed for quitting the electric braking of the vehicle, so that the electric braking force is reduced to zero at the same time when the vehicle speed is reduced to zero, and the vehicle is prevented from slipping backwards.
In order to achieve the above object, a third object of the present invention is to provide a vehicle including a brake apparatus of the vehicle as described in the above embodiment.
In order to achieve the above object, a fourth aspect of the present invention provides a traction controller, including a memory, a processor; wherein the processor executes a program corresponding to the executable program code by reading the executable program code stored in the memory, for implementing the braking method of the vehicle as described in any one of the above embodiments.
In order to achieve the above object, a fifth aspect embodiment of the present invention proposes a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements a braking method of a vehicle as described in the above embodiments.
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
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic flow chart of a braking method for a vehicle according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a braking method for a vehicle according to an embodiment of the present invention;
FIG. 3 is a flowchart illustrating a method for obtaining a target vehicle speed for triggering electric braking to exit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a braking device of a vehicle according to an embodiment of the present invention; and
fig. 5 is a schematic structural diagram of a traction controller according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A vehicle, a braking method, a device, an apparatus, and a medium thereof according to embodiments of the present invention are described below with reference to the accompanying drawings.
Fig. 1 is a schematic flow chart of a braking method for a vehicle according to an embodiment of the present invention, and as shown in fig. 1, the braking method for a vehicle includes the following steps:
step 101, obtaining vehicle state information, and generating a braking request of a vehicle according to the vehicle state information, wherein the vehicle state information comprises a current load, a level, a TCU activation number and a vehicle grouping of the vehicle.
Specifically, when a vehicle starts to brake, a main Control Unit (TCU) in the traction controller receives vehicle state information sent by a vehicle Control Unit (CCU), where the vehicle state information may include information such as a current load, a level, an activated number of TCUs, and a vehicle consist of the vehicle. The current level of the vehicle may be a control level in a control system of the vehicle within a preset range, for example, the level of the vehicle is within a [0,100] interval, or may be throttle information of the vehicle, or traction information within other corresponding ranges, and the like.
Further, the TCU calculates the braking torque required by the electric braking of the vehicle in the braking process according to the received vehicle state information, wherein the braking torque is the torque output by the driving motor when no mechanical braking is involved, and then generates a braking request according to the calculated braking torque, so that the vehicle can be controlled to perform the electric braking according to the braking request subsequently.
And 102, controlling the vehicle to perform electric braking according to the braking request, and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process.
Specifically, after the TCU generates a braking request, the vehicle speed is reduced by controlling the motor of the vehicle to output a braking torque, so as to electrically brake the vehicle. And acquiring the speed of the vehicle in real time in the braking process of the vehicle, comparing the acquired speed with the calculated target speed for finishing electric braking to judge whether the electric braking is finished, and unloading the braking torque of the motor to finish the electric braking when the speed of the vehicle is reduced to the target speed, so that the electric braking force is reduced to zero when the speed of the vehicle is reduced to zero, and the backward slip of the vehicle caused by the fact that the reverse braking torque still exists in the motor after the vehicle stops is avoided. Therefore, the vehicle is controlled to perform electric braking in the whole braking process.
According to the vehicle braking method, the vehicle state information sent by the vehicle controller is received, the vehicle braking request is generated according to the vehicle state information, so that the vehicle is controlled to perform electric braking, and whether the electric braking is finished or not is judged according to the current vehicle speed of the vehicle in the electric braking process. In the braking process of the vehicle, the purpose of braking the vehicle can be realized through electric braking, and mechanical braking is not adopted in the braking process, so that the abrasion to a braking system in the braking process is reduced, the vehicle is more stable in the braking process, the noise generated by braking is reduced, and the comfort of driving and riding the vehicle by a user is improved.
In order to more clearly describe a specific implementation process of controlling the vehicle to perform electric braking in the whole braking process, the embodiment of the invention further provides a specific vehicle braking method, and fig. 2 is a flowchart of the specific vehicle braking method provided by the embodiment of the invention.
As shown in fig. 2, the method comprises the steps of:
step 201, extracting the braking torque of the vehicle from the braking request, and electrically braking the vehicle by using the braking torque.
Specifically, after receiving the state information of the vehicle, the TCU first calculates the braking torque of the vehicle according to the state information of the vehicle.
As a possible implementation mode, the TCU firstly extracts the current level x of the vehicle, the vehicle weight M of the whole vehicle, the vehicle grouping and the rotating mass M of a single vehicle from the vehicle state informationrThe rotational mass of the single-unit vehicle is equivalent to the rotational kinetic energy of a rotating member such as a wheel of the single-unit vehicle.
And then, according to a mapping relation between the pre-stored vehicle level and the equivalent braking acceleration coefficient Kb, obtaining the equivalent braking acceleration coefficient Kb corresponding to the current level of the vehicle, and dividing the whole vehicle weight by the vehicle grouping number to obtain the single-section vehicle weight m of the vehicle. Further, an initial value Tb of the braking torque currently required by the vehicle is determined by the following formula:
Tb＝{[(m+mr)*1000*Kb*x]*R}/(Kn*Kr)
and finally, judging whether the filtered braking torque initial value is in a preset torque limit value range under a vehicle failure state, and if the braking torque initial value is determined to be in the torque limit value range, taking the braking torque initial value as the braking torque for controlling the vehicle to brake.
Furthermore, after the TCU obtains the braking torque of the vehicle, it generates a braking request for outputting the braking torque, and sends the braking request to a motor controller (DCU) in the traction controller, and after the DCU receives the output request, it extracts the braking torque from the braking request, and controls the motor of the vehicle to output the braking torque, so as to meet the braking force requirement of the vehicle, and control the vehicle to perform electric braking during braking, so as to reduce the vehicle speed to zero.
Step 202, in the electric braking process, obtaining a target speed of the vehicle for triggering the electric braking to exit.
It should be noted that, after the vehicle is braked, when the vehicle speed is reduced to the target vehicle speed triggering the electric brake to quit, the TCU needs to control the DCU to unload the braking torque of the motor, so as to ensure that the braking torque of the motor is also unloaded when the vehicle speed is reduced to zero, and avoid the backward slip of the vehicle caused by the fact that the motor still has reverse braking torque after the vehicle is stopped.
During specific implementation, the TCU calculates the target speed of the vehicle for triggering the electric brake to quit according to the state information of the vehicle, so that whether the current speed of the vehicle is reduced to the target speed or not can be judged conveniently.
Step 203, judging whether the current speed of the vehicle is decelerated to the target speed.
It can be understood that, when the vehicle starts braking, the speed of the vehicle is relatively high, and is usually much greater than the target vehicle speed at which the vehicle triggers electric braking to exit, so in order to save computing resources, in an embodiment of the present invention, after the vehicle starts braking, the TCU first calculates the current vehicle speed of the vehicle according to the motor rotation speed sent by the DCU, and then determines whether the current vehicle speed of the vehicle decelerates to a preset vehicle speed, where the preset vehicle speed is a vehicle speed that is greater than the target vehicle speed at which the electric braking exits within a certain range under different braking torques obtained through a large number of experiments.
And then, after determining that the current speed of the vehicle is reduced to the preset speed, the TCU makes a difference between the calculated current speed of the vehicle and the obtained target speed so as to judge whether the current speed of the vehicle is reduced to the target speed.
And step 204, if the current vehicle speed is reduced to the target vehicle speed, controlling the vehicle to exit the electric brake, and unloading the torque of the electric brake.
Specifically, if it is determined that the current vehicle speed is decelerated to the target vehicle speed, the TCU controls the vehicle to exit the electric brake, and sends a brake torque unloading command to the DCU to unload the torque of the electric brake.
Wherein, when unloading the electric braking torque, the torque unloading speed K determined when the target vehicle speed is obtained can be usedTAnd the torque unloading time t is used for unloading the torque, so that the step value of the torque unloading is in a proper range, the impact degree in the vehicle braking process is reduced while the torque unloading is ensured to be finished, and the comfort of driving and riding the vehicle is improved.
Furthermore, when the vehicle speed is reduced to zero, the braking torque of the motor is also unloaded, so that the backward slipping of the vehicle caused by the reverse braking torque of the motor after the vehicle stops is avoided.
Furthermore, when the vehicle is braked, that is, the vehicle stops, in order to improve the stability of parking of the vehicle, optionally, the vehicle may be controlled to apply mechanical brake, and parking of the vehicle is assisted by the mechanical brake force, so that displacement caused by the influence of the external environment after the vehicle stops is avoided, and the safety of parking of the vehicle is improved.
In order to describe a method for calculating a target vehicle speed of a vehicle triggering electric brake to exit more clearly, the embodiment of the invention also provides a method for acquiring the target vehicle speed triggering electric brake to exit. Fig. 3 is a flowchart illustrating a method for obtaining a target vehicle speed for triggering electric brake to exit according to an embodiment of the present invention.
As shown in fig. 3, the method comprises the steps of:
step 301, obtaining the total vehicle weight, the tire radius, the torque unloading rate and the gear ratio of the vehicle.
Specifically, as a possible implementation manner, a sensor is arranged on the vehicle in advance to detect the current total vehicle weight M of the vehiclevAnd then transmits the detected data to the TCU through the CAN bus. Meanwhile, the TCU sends the current load, the motor speed and the running state of the vehicle according to the CCUObtaining the torque unloading speed K corresponding to the braking torque in the braking process according to the vehicle state information such as the stateT. For example, when the current load of the vehicle is large, the motor speed is large, and the predicted torque unloading time is short according to the stopping distance, the calculated torque unloading rate K isTLarger, when the current load and motor speed of the vehicle are smaller, and the braking demand of the vehicle is lower, the calculated torque unloading rate K isTIs smaller.
Further, the CCU reads the pre-stored tire radius R and gear ratio K of the current vehiclerAnd the tire radius R and the gear ratio K of the current vehicle are calculatedrSent to the TCU.
Step 302, obtaining the maximum deceleration of the vehicle according to the maximum torque of the vehicle.
Specifically, it can be understood that, during unloading of the torque, the torque of the motor is gradually reduced, and therefore the braking force generated by the motor is gradually reduced, and when the braking force of the motor is reduced, the acceleration of the vehicle is also reduced accordingly. Therefore, at the initial moment of unloading the torque, the torque of the vehicle is the maximum torque during unloading the torque of the vehicle, the current deceleration of the vehicle is the maximum deceleration during unloading the torque, and since the braking acceleration of the vehicle has a mapping relation with the level of the vehicle, the maximum deceleration of the vehicle can be obtained according to the current level of the vehicle sent by the CCU at the moment when the torque of the vehicle is maximum, for example, the level 1-100 and the level 0.01-1m/s of the vehicle are preset2When the current level of the vehicle transmitted by the CCU at the time point when the torque of the vehicle is maximum is 50, the maximum deceleration a of the vehicle can be obtained from the mapvIs 0.5m/s2。
And step 303, acquiring torque unloading time required by the vehicle to complete torque unloading according to the weight of the whole vehicle, the radius of the tire, the absolute value of the maximum deceleration, the torque unloading rate and the gear ratio.
Specifically, it can be understood that the torque unloading time is the magnitude of the torque divided by the unloading rate of the torque, i.e. the torque unloading time required by the vehicle to complete the torque unloading can be calculated by the following formula (1):
wherein, TmIs the torque at the motor end. And TmThe calculation can be performed by the following formula (2):
wherein, TrThe wheel end torque can be calculated by multiplying the braking force of the vehicle by the radius of the tire, and then multiplying the absolute value of the maximum deceleration of the vehicle obtained in the step by the weight M of the whole vehiclevThe braking force of the vehicle is replaced, resulting in equation (2).
Further, after the formula (2) is substituted into the formula (1), the torque unloading time required by the vehicle to complete the torque unloading can be obtained according to the vehicle weight, the tire radius, the absolute value of the maximum deceleration, the torque unloading rate and the gear ratio, that is, the torque unloading time t required by the vehicle to complete the torque unloading is calculated through the following formula (3).
And step 304, acquiring deceleration of the vehicle in the process of finishing torque unloading according to the maximum deceleration and a preset equivalent acceleration coefficient.
Specifically, the torque unloading rate K is determined by the torque unloading processTIs constant, so that the braking torque of the motor is changed linearly during the unloading process, so that the equivalent deceleration of the vehicle during the unloading process is approximate to the maximum deceleration avAnd further, multiplying the equivalent deceleration by a preset equivalent acceleration coefficient KtThe deceleration during the completion of the torque off-loading of the vehicle can be obtained, that is, the deceleration during the completion of the torque off-loading of the vehicle can be calculated by the following formula (4):
and 305, acquiring a target vehicle speed according to the torque unloading time and the deceleration in the torque unloading process.
Specifically, when the vehicle is traveling during torque unloading, the speed of the vehicle may be given by the formula vt＝v0+ at is calculated, where v0The target vehicle speed for triggering the electric brake to exit. When the vehicle has finished braking, i.e. vtWhen 0 is taken, the target vehicle speed v for triggering the electric brake to quit of the vehicle can be calculated through the following formula (5)0：
v0Arbitrary formula (5)
And then, after the calculated torque unloading time t required by the vehicle to complete the torque unloading and the deceleration a during the torque unloading process of the vehicle are substituted into the formula (5), the target vehicle speed of the vehicle for triggering the electric brake to quit can be obtained.
It should be noted that, in practical applications, the external environmental factors or the time taken by the TCU to perform the above steps may affect the calculated target vehicle speed, so as to improve the accuracy of the calculated target vehicle speed at which the vehicle triggers electric braking to exit, and avoid displacement of the vehicle after braking is completed, in an embodiment of the present invention, the calculated torque unloading time and the deceleration during the torque unloading process of the vehicle may also be corrected.
Specifically, first, after obtaining the torque unloading time required by the vehicle to complete the torque unloading, the TCU may further correct the torque unloading time by using the torque filtering delay time of the vehicle, that is, correct the calculated torque unloading time by the following formula (6):
wherein, tfThe torque filtering delay time is the torque filtering delay time, and the torque filtering takes a certain time, so the torque unloading time after the torque filtering delay time is added is the time when the torque unloading of the vehicle is actually finishedAnd the accuracy and the reliability of the calculated torque unloading time are improved.
Then, it is understood that during the braking of the vehicle, the gravity acceleration component in the slope direction caused by the ground friction or the gradient may affect the running of the vehicle, change the deceleration of the vehicle, so that after the deceleration during the torque unloading of the vehicle is obtained, the TCU may further obtain the current gradient θ and the current ground adhesion coefficient of the vehicle through the on-board navigation device or the transponder device on the running route, and then obtain the ramp deceleration a according to the current gradient θθThat is, the hill deceleration a is calculated by the following formula (7)θ：
aθG θ equation (7)
Wherein g is the acceleration of gravity. When the gradient is small, θ can be approximately regarded as sin θ tan θ, and thus the ramp deceleration aθMay be approximately equal to g θ.
Furthermore, the TCU is based on the current ground adhesion coefficient and the current vehicle weight M of the whole vehiclevObtaining the deceleration a caused by the friction forcefFinally, the deceleration during unloading is corrected by using the deceleration caused by the slope deceleration and the friction force, that is, the deceleration during unloading is calculated by the following formula (8):
furthermore, substituting the formula (6) and the formula (8) into the formula (5) can obtain a formula for calculating the corrected target vehicle speed for triggering the electric brake to quit, namely the following formula (9)
Therefore, the TCU calculates the target vehicle speed for triggering the electric brake to quit according to the acquired vehicle state parameters, and corrects the calculated target vehicle speed through the torque filtering delay time, the ramp deceleration and the deceleration caused by the friction force, so that the accuracy of the acquired target vehicle speed is improved.
In summary, in the braking method of the vehicle according to the embodiment of the present invention, the vehicle state information is firstly obtained, the braking request of the vehicle is generated according to the vehicle state information, then the vehicle is controlled to perform electric braking in the braking process according to the braking request, and whether to end the electric braking is determined according to the current vehicle speed of the vehicle in the electric braking process. Therefore, in the vehicle braking process, the purpose of vehicle braking can be achieved through electric braking, mechanical braking is not adopted in the braking process, abrasion to a braking system in the braking process is reduced, the vehicle is more stable in the braking process, noise generated by braking is reduced, and comfort of a user in driving and riding the vehicle is improved. Further, the method can calculate the braking torque currently required by the vehicle according to the state information of the vehicle so that the vehicle can output the torque for braking, and after the vehicle is braked, the electric braking torque is unloaded when the vehicle speed is reduced to the target vehicle speed for quitting the electric braking of the vehicle, so that the electric braking force is reduced to zero at the same time when the vehicle speed is reduced to zero, and the vehicle is prevented from rolling backwards.
In order to implement the above embodiments, the embodiments of the present invention further provide a braking device for a vehicle. Fig. 4 is a schematic structural diagram of a braking device of a vehicle according to an embodiment of the present invention, and as shown in fig. 4, the braking device of the vehicle includes: a generation module 100 and a brake control module 200.
The generating module 100 is configured to obtain vehicle state information, and generate a braking request of a vehicle according to the vehicle state information, where the vehicle state information includes a current load, a level, a TCU activation number, and a vehicle code of the vehicle.
And the brake control module 200 is configured to control the vehicle to perform electric braking according to the braking request, and determine whether to end the electric braking according to the current vehicle speed of the vehicle during the electric braking.
In a possible implementation manner of the embodiment of the present invention, the brake control module 200 is further configured to extract a brake torque of the vehicle from the brake request, perform electric braking on the vehicle by using the brake torque, acquire a target vehicle speed of the vehicle, which triggers the electric brake to exit, during the electric braking, and determine whether a current vehicle speed of the vehicle is decelerated to the target vehicle speed, and if the current vehicle speed is decelerated to the target vehicle speed, control the vehicle to exit the electric brake, and unload the torque of the electric brake.
Specifically, the braking control module 200 is specifically configured to determine whether a current vehicle speed of the vehicle is reduced to a preset vehicle speed in a braking process, and if the current vehicle speed is reduced to the preset vehicle speed, obtain a target vehicle speed of the vehicle for triggering the electric brake to exit in real time.
Further, the braking control module 200 is specifically configured to obtain a total vehicle weight, a tire radius, a torque unloading rate, and a gear ratio of the vehicle, obtain a maximum deceleration of the vehicle according to the maximum torque of the vehicle, then obtain a torque unloading time required by the vehicle to complete torque unloading according to the total vehicle weight, the tire radius, an absolute value of the maximum deceleration, the torque unloading rate, and the gear ratio, obtain a deceleration of the vehicle in the process of completing torque unloading according to the maximum deceleration and a preset equivalent acceleration coefficient, and finally obtain a target vehicle speed according to the torque unloading time and the deceleration of the torque unloading process.
Furthermore, the brake control module 200 is further configured to correct the torque unloading time by using the torque filtering delay time of the vehicle after obtaining the torque unloading time required by the vehicle to complete the torque unloading. And after the deceleration of the vehicle in the process of unloading the torque is obtained, obtaining the current gradient and the current ground adhesion coefficient of the vehicle, then obtaining the ramp deceleration according to the current gradient, obtaining the deceleration caused by the friction force according to the current ground adhesion coefficient, and finally correcting the deceleration in the unloading process by using the ramp deceleration and the deceleration caused by the friction force.
It should be noted that the foregoing explanation of the embodiment of the vehicle braking method is also applicable to the vehicle braking device of this embodiment, and is not repeated herein.
In summary, in the braking apparatus for a vehicle according to the embodiment of the present invention, the braking method for a vehicle according to the embodiment of the present invention first obtains the vehicle state information, generates the braking request for the vehicle according to the vehicle state information, then controls the vehicle to perform electric braking according to the braking request, and determines whether to end the electric braking according to the current vehicle speed of the vehicle during the electric braking. Therefore, in the vehicle braking process, the purpose of vehicle braking can be achieved through electric braking, mechanical braking is not adopted in the braking process, abrasion to a braking system in the braking process is reduced, the vehicle is more stable in the braking process, noise generated by braking is reduced, and comfort of a user in driving and riding the vehicle is improved. Further, the device can calculate the braking torque currently required by the vehicle according to the state information of the vehicle so that the vehicle can output the torque for braking, and after the vehicle is braked, the electric braking torque is unloaded when the vehicle speed is reduced to the target vehicle speed for quitting the electric braking of the vehicle, so that the electric braking force is reduced to zero at the same time when the vehicle speed is reduced to zero, and the vehicle is prevented from slipping backwards.
In order to achieve the above embodiments, the present invention also proposes a vehicle including the brake device of the vehicle as described in the above embodiments.
In order to realize the embodiment, the invention further provides a traction controller.
Fig. 5 is a schematic structural diagram of a traction controller according to an embodiment of the present application. As shown in fig. 5, the traction controller 120 includes: a processor 121 and a memory 122; the memory 122 is used for storing executable program code; the processor 121 executes a program corresponding to the executable program code by reading the executable program code stored in the memory 122, for implementing the braking method of the vehicle as described in the above embodiment.
In order to achieve the above embodiments, the present invention also proposes a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the braking method of the vehicle as described in the above embodiments.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean 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 invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can 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). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can 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 should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A braking method of a vehicle, characterized by comprising the steps of:
acquiring vehicle state information, and generating a braking request of a vehicle according to the vehicle state information; the vehicle state information comprises the current load, the level, the TCU activation number and the vehicle grouping of the vehicle;
and controlling the vehicle to perform electric braking according to the braking request, and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process.
2. The method of claim 1, further comprising:
when the vehicle needs to be parked, the vehicle is controlled to apply mechanical brake to assist the parking of the vehicle.
3. The method of claim 1, wherein the controlling the vehicle to perform electric braking according to the braking request, and determining whether to end electric braking according to the current vehicle speed of the vehicle during electric braking comprises:
extracting a braking torque required by the vehicle from the braking request, and electrically braking the vehicle by using the braking torque;
in the electric braking process, acquiring a target speed of the vehicle for triggering the electric braking to exit;
judging whether the current speed of the vehicle is reduced to the target speed;
and if the current vehicle speed is decelerated to the target vehicle speed, controlling the vehicle to exit the electric brake and unloading the torque of the electric brake.
4. The method of claim 3, wherein the obtaining a target vehicle speed of the vehicle that triggers electric brake exit further comprises:
in the electric braking process, whether the current speed of the vehicle is reduced to a preset speed is judged, and if the current speed of the vehicle is reduced to the preset speed, a target speed of the vehicle for triggering the electric braking to exit is obtained in real time.
5. The method of claim 3 or 4, wherein the obtaining a target vehicle speed of the vehicle that triggers electric brake exit comprises:
acquiring the whole vehicle weight, the tire radius, the torque unloading rate and the gear ratio of the vehicle;
acquiring the maximum deceleration of the vehicle according to the maximum torque of the vehicle;
acquiring torque unloading time required by the vehicle to finish torque unloading according to the vehicle weight, the tire radius, the absolute value of the maximum deceleration, the torque unloading rate and the gear ratio;
acquiring deceleration of the vehicle in the process of finishing torque unloading according to the maximum deceleration and a preset equivalent acceleration coefficient;
and acquiring the target vehicle speed according to the torque unloading time and the deceleration in the torque unloading process.
6. The method of claim 5, wherein after obtaining the torque off-load time required for the vehicle to complete torque off-load, further comprising:
and correcting the torque unloading time by using the torque filtering delay time of the vehicle.
7. The method of claim 6, wherein after said obtaining a deceleration during torque off-loading of the vehicle, further comprising:
acquiring the current gradient and the current ground adhesion coefficient of the vehicle;
acquiring ramp deceleration according to the current gradient;
acquiring deceleration caused by friction according to the current ground adhesion coefficient;
and correcting the deceleration during the unloading process by using the slope deceleration and the deceleration caused by the friction force.
8. A brake apparatus for a vehicle, characterized by comprising:
the generating module is used for acquiring vehicle state information and generating a braking request of a vehicle according to the vehicle state information; the vehicle state information comprises the current load, the level, the TCU activation number and the vehicle grouping of the vehicle;
and the brake control module is used for controlling the vehicle to perform electric braking according to the brake request and judging whether to finish the electric braking according to the current speed of the vehicle in the electric braking process.
9. A vehicle, characterized by comprising: the braking device of a vehicle according to claim 8.
10. A traction controller comprising a memory, a processor;
wherein the processor executes a program corresponding to the executable program code by reading the executable program code stored in the memory for implementing a braking method of a vehicle according to any one of claims 1 to 7.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811584255.1A CN111348023B (en) | 2018-12-24 | 2018-12-24 | Vehicle and braking method and device thereof |
| BR112021012313-0A BR112021012313A2 (en) | 2018-12-24 | 2019-12-23 | VEHICLE AND BRAKING METHOD AND EQUIPMENT FOR THE SAME |
| PCT/CN2019/127461 WO2020135340A1 (en) | 2018-12-24 | 2019-12-23 | Vehicle and braking method and device therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811584255.1A CN111348023B (en) | 2018-12-24 | 2018-12-24 | Vehicle and braking method and device thereof |
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| Publication Number | Publication Date |
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| CN111348023A true CN111348023A (en) | 2020-06-30 |
| CN111348023B CN111348023B (en) | 2021-07-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201811584255.1A Active CN111348023B (en) | 2018-12-24 | 2018-12-24 | Vehicle and braking method and device thereof |
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| Country | Link |
|---|---|
| CN (1) | CN111348023B (en) |
| BR (1) | BR112021012313A2 (en) |
| WO (1) | WO2020135340A1 (en) |
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| CN111775919A (en) * | 2020-07-24 | 2020-10-16 | 中车株洲电力机车有限公司 | Locomotive auxiliary braking method and device |
| CN112659907A (en) * | 2021-01-05 | 2021-04-16 | 奇瑞新能源汽车股份有限公司 | Electric braking parking method and device for vehicle, motor controller and vehicle |
| CN114179859A (en) * | 2021-12-16 | 2022-03-15 | 交控科技股份有限公司 | Acceleration-based train control method and device |
| CN114294350A (en) * | 2021-12-10 | 2022-04-08 | 重庆长安汽车股份有限公司 | DCT vehicle type braking parking condition clutch torque control method and system and vehicle |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114162066B (en) * | 2021-11-30 | 2023-12-19 | 东风越野车有限公司 | Method and equipment for controlling withdrawal and taking force of power takeoff for vehicle |
| CN115009239B (en) * | 2022-07-07 | 2023-11-07 | 浙江极氪智能科技有限公司 | Parking method, device, equipment and storage medium for vehicle |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN111348023B (en) | 2021-07-20 |
| BR112021012313A2 (en) | 2021-08-31 |
| WO2020135340A1 (en) | 2020-07-02 |
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