CN115892007A - Steering braking method, device, equipment and medium under emergency working condition - Google Patents
Steering braking method, device, equipment and medium under emergency working condition Download PDFInfo
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Abstract
The application provides a steering braking method, a device, equipment and a medium under an emergency working condition. The method comprises the following steps: acquiring the road curvature of a current road and the driving state of a vehicle on the current road; if the road curvature is larger than the preset curvature, acquiring the axle load transfer rate of the vehicle according to the driving state; acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the driving state of the vehicle; adjusting an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusting a wheel turning angle of the vehicle according to the desired lateral acceleration. The method effectively combines the transverse acceleration and the longitudinal acceleration to brake and control the running of the vehicle, and achieves accurate and safe braking effect.
Description
Technical Field
The application relates to the technical field of vehicle control, in particular to a steering braking method, a device, equipment and a medium under an emergency working condition.
Background
With the continuous increase of road mileage and the continuous increase of the load transportation volume carried by the commercial vehicle, higher level requirements are provided for the driving safety and reliability of the commercial vehicle. Under emergency conditions, the commercial vehicle is required to react in time so as to avoid drifting and overturning.
In the prior art, a transverse control method is mostly adopted, the steering wheel angle is controlled under the condition that the vehicle speed is not changed, the running state of the commercial vehicle is adjusted, or the track of the commercial vehicle is adjusted by acquiring the current position and the target position of the commercial vehicle, so that the transverse tracking control of the commercial vehicle is realized, or the track of the commercial vehicle is adjusted by calculating the longitudinal safe distance and the lane changing safe distance of the commercial vehicle; the factors that are considered in these methods to influence the braking of the commercial vehicle are not comprehensive enough, so that a more stable, reliable and comprehensive control method is needed.
Disclosure of Invention
The application provides a steering braking method, a steering braking device, steering braking equipment and a steering braking medium under an emergency condition, and aims to solve the problem that braking control is not accurate enough due to the fact that data adopted by a braking control mode are not comprehensive enough in the prior art.
In a first aspect, the present application provides a steering braking method under an emergency condition, including:
acquiring the road curvature of a current road and the driving state of a vehicle on the current road;
if the road curvature is larger than the preset curvature, acquiring the axle load transfer rate of the vehicle according to the driving state;
acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the driving state of the vehicle;
adjusting an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusting a wheel rotation angle of the vehicle according to the desired lateral acceleration.
In one possible implementation, the obtaining of the desired longitudinal acceleration and the desired lateral acceleration according to the axle load transfer rate and the driving state of the vehicle includes:
if the axle load transfer rate is smaller than a safety threshold, acquiring the expected transverse acceleration according to the wheel rotation angle and the vehicle speed correction value in the driving state, and acquiring the expected longitudinal acceleration according to the road adhesion;
and if the axle load transfer rate is greater than or equal to a safety threshold, acquiring the expected transverse acceleration according to the transverse acceleration in the driving state, the safety threshold and the axle load transfer rate, and acquiring the expected longitudinal acceleration according to the expected transverse acceleration and the ground friction coefficient.
In a possible implementation manner, the obtaining of the axle load transfer rate of the vehicle according to the driving state includes:
and acquiring the axle load transfer rate according to the vertical loads of the four wheels of the vehicle in the running state.
In one possible implementation, the obtaining the desired lateral acceleration according to the wheel rotation angle and the vehicle speed correction value in the driving state, and obtaining the desired longitudinal acceleration according to the road adhesion force includes:
obtaining expected transverse force according to the wheel rotation angle and the vehicle speed correction value;
acquiring the expected lateral acceleration according to the expected lateral force and the mass of the vehicle;
a desired longitudinal force is obtained from the desired lateral force and a frictional force of the vehicle, and the desired longitudinal acceleration is obtained from the desired longitudinal force and a mass of the vehicle.
In one possible implementation, before obtaining the desired lateral force according to the corrected value of the wheel rotation angle and the vehicle speed, the method further includes:
if the longitudinal speed in the running state is less than or equal to the safe speed, acquiring the speed correction value according to the safe speed;
and if the longitudinal speed in the running state is greater than the safe speed, taking the longitudinal speed in the running state as the vehicle speed correction value.
In one possible implementation, the obtaining the desired lateral force according to the wheel rotation angle and the vehicle speed correction value includes:
acquiring a first parameter according to the friction coefficient, the gravity acceleration and the mass of the vehicle;
acquiring a second parameter according to the wheel rotation angle, the vehicle speed correction value and the mass of the vehicle;
and acquiring the expected transverse force according to the ratio of the first parameter and the second parameter.
In one possible implementation, the obtaining the desired lateral acceleration according to the lateral acceleration in the driving state, the safety threshold, and the axle load transfer rate includes:
acquiring the ratio of the safety threshold to the axle load transfer rate, and acquiring the expected transverse acceleration according to the ratio and the transverse acceleration;
correspondingly, the obtaining the expected longitudinal acceleration according to the expected transverse acceleration and the ground friction coefficient comprises:
acquiring friction acceleration according to the ground friction coefficient and the gravity acceleration;
and acquiring the expected longitudinal acceleration according to the friction acceleration and the expected transverse acceleration.
In a second aspect, the present application provides a steering brake device under an emergency condition, including:
the system comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the road curvature of the current road and the driving state of a vehicle on the current road;
the judging module is used for acquiring the axle load transfer rate of the vehicle according to the driving state if the road curvature is larger than the preset curvature;
the second acquisition module is used for acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the running state of the vehicle;
and the processing module is used for adjusting the opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration and adjusting the wheel rotation angle of the vehicle according to the expected lateral acceleration.
In a third aspect, the present application provides a steering brake device under an emergency condition, comprising: at least one processor and memory;
the memory stores computer-executable instructions;
the at least one processor executes the computer-executable instructions stored by the memory to cause the at least one processor to perform the method of steering braking in an emergency condition as described above.
In a fourth aspect, the present application provides a computer readable storage medium, on which a computer program is stored, which computer program, when being executed by a processor, realizes the steps of the steering braking method in an emergency situation as described above.
According to the steering braking method, the device, the equipment and the medium under the emergency working condition, the road curvature of the current road and the running state of a vehicle on the current road are obtained; if the road curvature is larger than the preset curvature, acquiring the axle load transfer rate of the vehicle according to the driving state; acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the driving state of the vehicle; adjusting an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusting a wheel turning angle of the vehicle according to the desired lateral acceleration. According to the method, the transverse acceleration and the longitudinal acceleration are effectively combined to brake and control the running of the vehicle, so that an accurate and safe braking effect is achieved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1 is a schematic illustration of a steering brake under an emergency condition as set forth herein;
FIG. 2 is a first flowchart of a steering braking method under an emergency condition according to the present disclosure;
FIG. 3 is a second flowchart of a steering braking method under an emergency condition according to the present application;
FIG. 4 is a flow chart of a third method of steering braking under an emergency condition according to the present application;
FIG. 5 is a comparison of paths of a steering braking method under an emergency condition as set forth in the present application;
FIG. 6 is a comparison of vehicle speed for a steering braking method under emergency conditions as proposed herein;
FIG. 7 is a diagram of a steering braking device under an emergency condition according to an embodiment of the present invention;
fig. 8 is a hardware schematic diagram of a steering brake device under an emergency condition according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
With the increasing road mileage, the load carrying transport capacity of the commercial vehicle is also increasing, and the load carrying transport capacity of the commercial vehicle also puts higher requirements on the safe and reliable driving on the road. In the prior art, the commercial vehicle needs a reasonable braking mode to control vehicle braking when meeting emergency conditions, the traditional braking control mostly adopts transverse control, and the steering wheel rotating angle is controlled under the condition that the vehicle speed is not changed. However, the existing method considers single factors, so the control effect is more and more difficult to meet the higher braking requirement of the existing commercial vehicle.
The present application thus proposes a method of steering braking in emergency conditions that may take into account a combination of ground adhesion, lateral acceleration and longitudinal acceleration.
The following describes a steering braking method under an emergency condition proposed by the present application with reference to fig. 1, so as to control braking of a commercial vehicle under the emergency condition.
Fig. 1 is a schematic view of a steering brake in an emergency condition according to the present application. As shown in fig. 1, the system includes: a steering wheel 101, a brake pedal 102 and wheels 103, and further includes sensors that can monitor a driving curve during the driving of the vehicle;
under an emergency condition, a driving curve of a vehicle in the driving process is obtained through a sensor, and driving data of the vehicle is obtained according to a state sensing module in the vehicle, for example, when the vehicle encounters a large turning state, the vehicle needs to be steered and braked, so that the vehicle can stably drive or stably stop on a curve; the sensors include a Remote control Unit (RMU) which can be used to obtain a driving curve during driving of the vehicle, the degree of curvature of the driving curve is represented by the curvature of the road, and a state sensing module inside the vehicle can obtain the speed, the vertical load and the wheel rotation angle of the vehicle.
When the turning angle of the vehicle reaches a certain degree, the vehicle may turn over, which is not beneficial to the safe driving of the vehicle, so that when the curvature of the road is greater than the preset curvature, the driving state of the vehicle needs to be corrected, and the vehicle can be ensured to be kept in the safe driving state; when the curvature of the road is less than or equal to the preset curvature, the running state of the vehicle may not be corrected, or appropriate deceleration may be performed according to the actual running condition. In the case where it is determined that the curvature of the road is less than or equal to the preset curvature, the vehicle control may be performed in any safe driving state, and the present embodiment is not particularly limited.
And under the condition that the curvature of the road is determined to be larger than the preset curvature, the running state of the vehicle on the current road needs to be acquired in real time in the process of correcting the running state of the vehicle, and the actual value and the expected value are compared so as to be continuously close to the expected value.
For example, when a vehicle runs on a curve, the vehicle cannot run at a running speed under a straight road condition, and whether the vehicle needs to enter a steering braking state or not needs to be acquired from the existing road surface data, and if the degree of curvature of the current running curve does not reach the degree of influence on the running of the vehicle, the vehicle can continue to run according to the original running state;
if the bending degree of the current vehicle running curve is too large, namely the road curvature is too large, the vehicle running is possibly influenced, the wheels 103 can be controlled to rotate left and right by changing the steering wheel 101, and after the wheels are rotated left and right, the transverse stress of the vehicle can be changed, so that the transverse acceleration is changed, in the changing process, the expected transverse acceleration which the vehicle should reach when the vehicle turns can be obtained in real time, the vehicle is controlled according to the expected transverse acceleration, and the vehicle running can gradually reach the safe running standard;
meanwhile, the longitudinal acceleration of the vehicle can be adjusted by changing the opening and closing degree of the brake pedal 102, and in the process, the opening and closing degree of the brake pedal 102 needs to be adjusted while the expected longitudinal acceleration is acquired, so that the vehicle finally gradually reaches the safe driving standard.
In the embodiment, the expected lateral acceleration and the expected longitudinal acceleration of the vehicle are updated in real time, and the steering wheel 101 and the brake pedal 102 of the vehicle are adjusted according to the expected lateral acceleration and the expected longitudinal acceleration, so that the vehicle runs in the expected acceleration (including the expected lateral acceleration and the expected longitudinal acceleration).
The following describes the situation of controlling the braking of the commercial vehicle in the steering braking method under the emergency condition proposed by the present application with reference to fig. 2.
Fig. 2 is a first flowchart of a steering braking method under an emergency condition according to the present application. As shown in fig. 2, the method includes:
s201, acquiring the curvature of the current road and the running state of the vehicle on the current road.
The road curvature of the road may indicate a degree of curvature of a curve encountered by the vehicle, and the vehicle may travel according to the curve, so the road curvature may reflect a turning condition of the vehicle, and a larger road curvature may indicate a larger angle at which the vehicle turns.
The driving state can be represented by driving parameters of the vehicle under different conditions, and the driving state comprises the following steps: longitudinal vehicle speed, lateral acceleration, wheel rotation angle and vertical load of the wheel; the longitudinal speed and the wheel rotation angle can be used for acquiring expected lateral acceleration, the lateral acceleration can also be used for acquiring expected lateral acceleration, and the different manners for acquiring the expected lateral acceleration can be used under the conditions of different axle load transfer rates; the desired longitudinal acceleration can be obtained according to the desired lateral acceleration; the vertical load of the wheel is used to obtain the axle load transfer rate. These driving states will be described in the following steps for specific use cases.
Under the actual driving condition, the sensor can acquire the road curvature of the road in real time until the road curvature is restored to the preset curvature, and the driving state of the vehicle does not need to be corrected.
And S202, if the curvature of the road is larger than a preset curvature, acquiring the axle load transfer rate of the vehicle according to the running state.
After the road curvature is obtained, judging, and under the condition that the road curvature is determined to be larger than the preset curvature, further obtaining the driving state of the vehicle, wherein the driving state comprises the stress condition of the vehicle, and the axle load transfer rate can be obtained according to the stress condition of the vehicle; the axle load transfer rate represents the stress distribution condition of the vehicle, the vehicle generally has a front wheel and a rear wheel, if the stress of the front wheel or the rear wheel is too large, the gravity center of the vehicle is changed, and the vehicle can incline, so the running state of the vehicle can be adjusted according to the axle load transfer rate.
In the actual running process of the vehicle, the axle load transfer rate is obtained in the following mode:
optionally, the axle load transfer rate is obtained according to the vertical loads of four wheels of the vehicle in the driving state.
The stress conditions of the four wheels of the vehicle can be obtained by obtaining the vertical loads of the four wheels of the vehicle in a running state, and a specific formula for obtaining the axle load transfer rate LTR according to each vertical load is as follows:
wherein, the axle load transfer rate LTR takes an absolute value; f l1 Vertical load of the left front wheel; f l2 Vertical load for the left rear wheel; f r1 The right front wheel vertical load; f r2 Is the right rear wheel vertical load.
S203, acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the running state of the vehicle.
The axle load transfer rate of the vehicle can be used for indicating whether the vehicle is likely to roll, the roll is more likely to occur if the axle load transfer rate is larger, a safety threshold value can be set for the axle load transfer rate under the condition of acquiring the axle load transfer rate, the vehicle is not likely to roll when the axle load transfer rate is within the range of the safety threshold value, the vehicle can be safely driven, when the axle load transfer rate exceeds the safety threshold value, the expected longitudinal acceleration and the expected transverse acceleration can be acquired by combining the acquired driving state, the expected longitudinal acceleration and the expected transverse acceleration can be collectively called as the expected acceleration, and when the expected acceleration meets a certain condition, the speed and the axle load transfer rate of the vehicle can be controlled to achieve the state that the vehicle can safely drive.
S204, adjusting the opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration, and adjusting the wheel rotation angle of the vehicle according to the expected lateral acceleration.
The desired acceleration may be obtained from the actual acceleration, which may be controlled by the presence of a corresponding device on the vehicle, to adjust for the desired acceleration change.
The corresponding device on the vehicle comprises a brake pedal capable of controlling the longitudinal acceleration, the opening condition of the brake pedal can change the longitudinal force, namely, the longitudinal acceleration is changed, the larger the pressure on the brake pedal is, the smaller the opening is, the faster the vehicle is decelerated, and conversely, the slower the vehicle is decelerated; the steering wheel can adjust the wheel rotation angle of the vehicle correspondingly, and the transverse acceleration changes correspondingly.
In the embodiment of the application, the road curvature of the current road and the driving state of a vehicle on the current road are obtained; if the road curvature is larger than the preset curvature, acquiring the axle load transfer rate of the vehicle according to the driving state; acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the driving state of the vehicle; adjusting an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusting a wheel turning angle of the vehicle according to the desired lateral acceleration. According to the method, the transverse acceleration and the longitudinal acceleration are effectively combined to brake and control the running of the vehicle, so that an accurate and safe braking effect is achieved.
The method for controlling the braking of the commercial vehicle through the lateral acceleration and the longitudinal acceleration in the steering braking method under the emergency condition proposed by the present application is further described with reference to fig. 3 to 6.
Fig. 3 is a second flowchart of a steering braking method under an emergency condition according to the present application. As shown in fig. 3, the method includes:
and S301, judging whether the longitudinal speed in the running state is less than or equal to a safe speed, if so, executing S302, and otherwise, executing S303.
The longitudinal speed can be directly obtained, and a vehicle speed correction value is set according to the size of the longitudinal speed and the size of the safe vehicle speed, so that the safety of the vehicle can be ensured when the vehicle runs at the safe vehicle speed; if the longitudinal speed is less than or equal to the safe speed, the running speed of the vehicle is not fast, and the speed of the vehicle can be reduced properly and slightly; conversely, when the vehicle runs at an excessively high speed, the vehicle speed can be reduced appropriately and greatly.
Safe vehicle speed V safe The acquisition formula of (1) is as follows:
wherein k is 1 =2.33; m is the mass of the whole vehicle; g is the acceleration of gravity; k is a radical of 2 =9996; δ is a wheel rotation angle.
And S302, acquiring the vehicle speed correction value according to the safe vehicle speed, and executing S304.
If the longitudinal speed is less than or equal to the safe speed, the speed of the vehicle can be reduced by a proper small amplitude, namely, a vehicle speed correction value is obtained by taking the safe speed as a basis, and the larger the vehicle speed correction value is, the smaller the longitudinal acceleration is, and the slower the vehicle is decelerated.
At this time, the vehicle speed correction value V 0 The formula (c) is as follows:
V 0 ＝V safe +k 3
wherein k is 3 ＝0.00001。
And S303, taking the longitudinal vehicle speed in the running state as the vehicle speed correction value, and executing S304.
If the longitudinal vehicle speed is greater than the safe vehicle speed, the vehicle speed can be reduced properly and greatly, namely the longitudinal vehicle speed exceeding the safe vehicle speed is directly used as the vehicle speed correction value.
S304, if the axle load transfer rate is smaller than the safety threshold value, executing S305 to S309.
After a vehicle speed correction value required for correcting the expected acceleration of the vehicle is obtained, the mode of obtaining the expected acceleration is divided into two conditions according to the axle load transfer rate;
firstly, under the condition that the axle load transfer rate is smaller than the safety threshold, the adjustment of the expected acceleration can be carried out step by step, and the acceleration (comprising the actual acceleration and the expected acceleration) and the change condition of the expected acceleration can be tracked through a sensor at any time.
S305, acquiring a first parameter according to the friction coefficient, the gravity acceleration and the mass of the vehicle.
The friction coefficient can be directly obtained through the road surface type and the wheel type, and the gravity acceleration and the mass of the vehicle can also be directly obtained; the above parameters are obtained for the first parameter, which is used to obtain the desired lateral force.
And S306, acquiring a second parameter according to the wheel rotation angle, the vehicle speed correction value and the mass of the vehicle.
The wheel rotation angle is a current road running state acquired in advance, and the vehicle speed correction value is acquired in S301 to S303.
S307, acquiring the expected transverse force according to the ratio of the first parameter to the second parameter. Taking the ratio of the first parameter and the second parameter as the expected transverse force F lat1 The concrete formula is as follows:
F lat1 ＝k 4 /k 5
wherein k is 4 ＝mu 2 g 2 Is a first parameter; u is the coefficient of friction;
is the second parameter. />
And S308, acquiring the expected lateral acceleration according to the expected lateral force and the mass of the vehicle.
The ratio of the desired lateral force to the mass of the vehicle is taken as the desired lateral acceleration F lat1 The concrete formula is as follows:
a lat1 ＝F lat1 /m。
s309, acquiring an expected longitudinal force according to the expected transverse force and the friction force of the vehicle, and acquiring the expected longitudinal acceleration according to the expected longitudinal force and the mass of the vehicle.
Obtaining a desired longitudinal force F lon1 The specific formula of (2) is as follows:
obtaining a desired longitudinal acceleration a lon1 The specific formula of (A) is as follows:
a lon1 ＝F lon1 /m。
in the embodiment of the application, whether the longitudinal speed in the running state is smaller than or equal to a safe speed is judged, if yes, the speed correction value is obtained according to the safe speed, and if not, the longitudinal speed in the running state is used as the speed correction value. And if the axle load transfer rate is smaller than a safety threshold, acquiring a first parameter according to the friction coefficient, the gravity acceleration and the mass of the vehicle. And acquiring a second parameter according to the wheel rotation angle, the vehicle speed correction value and the mass of the vehicle. And acquiring the expected transverse force according to the ratio of the first parameter and the second parameter. And acquiring the expected lateral acceleration according to the expected lateral force and the mass of the vehicle. A desired longitudinal force is obtained from the desired lateral force and a frictional force of the vehicle, and the desired longitudinal acceleration is obtained from the desired longitudinal force and a mass of the vehicle. According to the method, when the axle load transfer rate is smaller than the safety threshold, the expected transverse acceleration and the expected longitudinal acceleration which can be used as braking bases are obtained through parameters such as the wheel rotating speed, the vehicle correction value and the friction coefficient, the expected acceleration is continuously updated in a real-time vehicle correction value adjusting mode, the purpose of constantly adjusting the proper braking speed is achieved, and the accuracy and the safety of the driving route of the vehicle are guaranteed.
Fig. 4 is a flow chart three of a steering braking method under an emergency condition according to the present application. As shown in fig. 4, the method includes:
s401, if the axle load transfer rate is larger than or equal to the safety threshold value, executing S402 to S403.
After a vehicle speed correction value required for correcting the expected acceleration of the vehicle is obtained, the mode of obtaining the expected acceleration is divided into two conditions according to the axle load transfer rate;
and secondly, when the axle load transfer rate is greater than or equal to the safety threshold, the expected acceleration can be adjusted to control the vehicle brake in a mode of directly decelerating through the expected acceleration.
S402, obtaining a ratio of the safety threshold to the axle load transfer rate, and obtaining the expected lateral acceleration according to the ratio and the lateral acceleration.
Taking the ratio of the safety threshold to the axle load transfer rate as a proportionality coefficient, and acquiring the expected transverse acceleration a according to the transverse acceleration lat2 The concrete formula is as follows:
wherein, F safe Is a safe threshold; a is y The lateral acceleration is the actual lateral acceleration of the vehicle traveling on the current road.
And S403, acquiring friction acceleration according to the ground friction coefficient and the gravity acceleration.
Obtaining frictional acceleration a u The specific formula of (A) is as follows:
a u ＝ug 2 。
s404, acquiring the expected longitudinal acceleration according to the friction acceleration and the expected transverse acceleration.
Acquiring expected longitudinal acceleration a according to the friction acceleration and the expected transverse acceleration lon2 The specific formula of (A) is as follows:
in the embodiment of the application, if the axle load transfer rate is greater than or equal to a safety threshold, a ratio of the safety threshold to the axle load transfer rate is obtained, and the expected lateral acceleration is obtained according to the ratio and the lateral acceleration. And acquiring friction acceleration according to the ground friction coefficient and the gravity acceleration. And acquiring the expected longitudinal acceleration according to the friction acceleration and the expected transverse acceleration. According to the method, when the axle load transfer rate is smaller than or equal to the safety threshold, parameters such as the transverse acceleration, the safety threshold, the axle load transfer rate and the like are used for obtaining the expected transverse acceleration and the expected longitudinal acceleration which can be used as braking bases, the expected acceleration is used for adjusting the vehicle, and the accuracy and the safety of the driving route of the vehicle are guaranteed.
Fig. 5 is a path comparison diagram of a steering braking method under an emergency condition according to the present application. As shown in fig. 5, the method of the present invention continuously obtains the driving track of the vehicle while tracking the acceleration, and simultaneously compares the driving track with the actual track (reference path, which may correspond to the curvature of the road) of the road where the vehicle is located and the proportional-integral-derivative control method in the prior art; as can be seen from fig. 5, the present invention is closer to the actual track, the prior art gradually deviates from the actual track during the braking process, and has a trend of being farther and farther, so the accuracy rate of the travel track correction is lower than that of the present invention, and the control accuracy of the present invention is higher.
FIG. 6 is a comparison of vehicle speed for a steering braking method under emergency conditions, as set forth in the present application. As shown in FIG. 6, the vehicle speed variation during braking is compared with the prior art proportional-integral-derivative control method; as can be seen from FIG. 6, the invention can realize more obvious deceleration effect under the condition of ensuring safe driving, and the vehicle speed change is more flexible.
Fig. 7 is a diagram of a steering braking device under an emergency condition according to an embodiment of the present invention, as shown in fig. 7, the device includes: a first obtaining module 701, a judging module 702, a second obtaining module 703 and a processing module 704;
the first obtaining module 701 is configured to obtain a road curvature of a current road and a driving state of a vehicle on the current road.
And the judging module 702 is configured to, if the road curvature is greater than a preset curvature, obtain an axle load transfer rate of the vehicle according to the driving state.
The second obtaining module 703 is configured to obtain an expected longitudinal acceleration and an expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state.
The second obtaining module 703 is further configured to obtain the expected lateral acceleration according to a wheel rotation angle and a vehicle speed correction value in the driving state and obtain the expected longitudinal acceleration according to a road adhesion force if the axle load transfer rate is smaller than a safety threshold;
and if the axle load transfer rate is greater than or equal to a safety threshold, acquiring the expected transverse acceleration according to the transverse acceleration in the driving state, the safety threshold and the axle load transfer rate, and acquiring the expected longitudinal acceleration according to the expected transverse acceleration and the ground friction coefficient.
The second obtaining module 703 is further configured to obtain an expected lateral force according to the wheel rotation angle and the vehicle speed correction value;
acquiring the expected lateral acceleration according to the expected lateral force and the mass of the vehicle;
a desired longitudinal force is obtained from the desired lateral force and a frictional force of the vehicle, and the desired longitudinal acceleration is obtained from the desired longitudinal force and a mass of the vehicle.
The second obtaining module 703 is further configured to obtain the vehicle speed correction value according to a safe vehicle speed if the longitudinal vehicle speed in the driving state is less than or equal to the safe vehicle speed;
and if the longitudinal speed in the running state is greater than the safe speed, taking the longitudinal speed in the running state as the vehicle speed correction value.
The second obtaining module 703 is further configured to obtain a first parameter according to the friction coefficient, the gravitational acceleration, and the mass of the vehicle;
acquiring a second parameter according to the wheel rotation angle, the vehicle speed correction value and the quality of the vehicle;
and acquiring the expected transverse force according to the ratio of the first parameter and the second parameter.
The second obtaining module 703 is further configured to obtain the expected lateral acceleration according to the lateral acceleration in the driving state, the safety threshold, and the axle load transfer rate, and includes:
acquiring the ratio of the safety threshold to the axle load transfer rate, and acquiring the expected transverse acceleration according to the ratio and the transverse acceleration;
correspondingly, the obtaining the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient comprises:
acquiring friction acceleration according to the ground friction coefficient and the gravity acceleration;
and acquiring the expected longitudinal acceleration according to the friction acceleration and the expected transverse acceleration.
A processing module 704 for adjusting an opening of a brake pedal of the vehicle according to the desired longitudinal acceleration and adjusting a wheel angle of the vehicle according to the desired lateral acceleration.
The application also provides a steering brake device under emergency conditions, including: at least one processor and memory;
the memory stores computer-executable instructions;
the at least one processor executes the computer-executable instructions stored by the memory to cause the at least one processor to perform a steering braking method in an emergency condition.
Fig. 8 is a hardware schematic diagram of a steering brake device under an emergency condition according to an embodiment of the present invention. As shown in fig. 8, the present embodiment provides a steering brake device 80 in an emergency condition, including: at least one processor 801 and a memory 802. The device 80 further comprises a communication component 803. The processor 801, the memory 802, and the communication unit 803 are connected by a bus 804.
In particular implementations, the at least one processor 801 executes computer-executable instructions stored by the memory 802 to cause the at least one processor 801 to perform a method of steering braking, such as in an upper emergency condition.
For a specific implementation process of the processor 801, reference may be made to the above method embodiments, which have similar implementation principles and technical effects, and details of this embodiment are not described herein again.
In the embodiment shown in fig. 8, it should be understood that the Processor may be a Central Processing Unit (CPU), other general purpose processors, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the present invention may be embodied directly in a hardware processor, or in a combination of the hardware and software modules within the processor.
The Memory may include a high-speed Memory (RAM) and may also include a Non-volatile Memory (NVM), such as at least one disk Memory.
The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the buses in the figures of the present application are not limited to only one bus or one type of bus.
The present application further provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, the method for braking steering under emergency conditions is implemented.
The computer-readable storage medium may be implemented by any type of volatile or non-volatile storage device or combination thereof, such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disk. A readable storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.
An exemplary readable storage medium is coupled to the processor such the processor can read information from, and write information to, the readable storage medium. Of course, the readable storage medium may also be an integral part of the processor. The processor and the readable storage medium may reside in an Application Specific Integrated Circuits (ASIC). Of course, the processor and the readable storage medium may also reside as discrete components in the apparatus.
The division of the units is only a logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk, and various media capable of storing program codes.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The foregoing program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains, and as may be applied to the details of construction and as follows in the construction and use of the invention, the invention is not limited to the precise arrangements set forth herein and as shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.
Claims (10)
1. A steering braking method under an emergency condition is characterized by comprising the following steps:
acquiring the road curvature of a current road and the driving state of a vehicle on the current road;
if the road curvature is larger than the preset curvature, acquiring the axle load transfer rate of the vehicle according to the driving state;
acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the driving state of the vehicle;
adjusting an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusting a wheel rotation angle of the vehicle according to the desired lateral acceleration.
2. The method according to claim 1, wherein said obtaining a desired longitudinal acceleration and a desired lateral acceleration based on an axle load transfer rate of the vehicle and the driving state comprises:
if the axle load transfer rate is smaller than a safety threshold, acquiring the expected transverse acceleration according to the wheel rotation angle and the vehicle speed correction value in the driving state, and acquiring the expected longitudinal acceleration according to the road adhesion;
and if the axle load transfer rate is greater than or equal to a safety threshold, acquiring the expected transverse acceleration according to the transverse acceleration in the driving state, the safety threshold and the axle load transfer rate, and acquiring the expected longitudinal acceleration according to the expected transverse acceleration and the ground friction coefficient.
3. The method according to claim 1, wherein the obtaining of the axle load transfer rate of the vehicle according to the driving state comprises:
and acquiring the axle load transfer rate according to the vertical loads of the four wheels of the vehicle in the running state.
4. The method according to claim 2, wherein the obtaining the desired lateral acceleration from the wheel rotation angle and the vehicle speed correction value in the running state and the obtaining the desired longitudinal acceleration from the road adhesion force comprise:
obtaining expected transverse force according to the wheel rotation angle and the vehicle speed correction value;
acquiring the expected lateral acceleration according to the expected lateral force and the mass of the vehicle;
a desired longitudinal force is obtained from the desired lateral force and a frictional force of the vehicle, and the desired longitudinal acceleration is obtained from the desired longitudinal force and a mass of the vehicle.
5. The method of claim 4, wherein before obtaining the desired lateral force based on the wheel angle and the vehicle speed correction, the method further comprises:
if the longitudinal speed in the running state is less than or equal to a safe speed, acquiring the speed correction value according to the safe speed;
and if the longitudinal speed in the running state is greater than the safe speed, taking the longitudinal speed in the running state as the vehicle speed correction value.
6. The method of claim 4, wherein said obtaining a desired lateral force based on the wheel angle, the vehicle speed correction value comprises:
acquiring a first parameter according to the friction coefficient, the gravity acceleration and the mass of the vehicle;
acquiring a second parameter according to the wheel rotation angle, the vehicle speed correction value and the mass of the vehicle;
and acquiring the expected transverse force according to the ratio of the first parameter and the second parameter.
7. The method according to claim 2, wherein the obtaining the desired lateral acceleration from the lateral acceleration in the driving state, the safety threshold, and the axle load transfer rate includes:
acquiring the ratio of the safety threshold to the axle load transfer rate, and acquiring the expected transverse acceleration according to the ratio and the transverse acceleration;
correspondingly, the obtaining the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient comprises:
acquiring friction acceleration according to the ground friction coefficient and the gravity acceleration;
and acquiring the expected longitudinal acceleration according to the friction acceleration and the expected transverse acceleration.
8. A steering brake device under an emergency condition, comprising:
the system comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the road curvature of a current road and the driving state of a vehicle on the current road;
the judging module is used for acquiring the axle load transfer rate of the vehicle according to the driving state if the curvature of the road is larger than the preset curvature;
the second acquisition module is used for acquiring expected longitudinal acceleration and expected transverse acceleration according to the axle load transfer rate and the running state of the vehicle;
and the processing module is used for adjusting the opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration and adjusting the wheel rotation angle of the vehicle according to the expected transverse acceleration.
9. A steering brake device under an emergency condition, characterized by comprising: at least one processor and memory;
the memory stores computer-executable instructions;
the at least one processor executing the computer-executable instructions stored by the memory causes the at least one processor to perform the method of emergency steering braking as claimed in any one of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method for steering braking in an emergency situation according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211419502.9A CN115892007A (en) | 2022-11-14 | 2022-11-14 | Steering braking method, device, equipment and medium under emergency working condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211419502.9A CN115892007A (en) | 2022-11-14 | 2022-11-14 | Steering braking method, device, equipment and medium under emergency working condition |
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| CN115892007A true CN115892007A (en) | 2023-04-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211419502.9A Pending CN115892007A (en) | 2022-11-14 | 2022-11-14 | Steering braking method, device, equipment and medium under emergency working condition |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116252763A (en) * | 2023-05-15 | 2023-06-13 | 广汽埃安新能源汽车股份有限公司 | Method and device for detecting reference vehicle speed of vehicle steering working condition |
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2022
- 2022-11-14 CN CN202211419502.9A patent/CN115892007A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116252763A (en) * | 2023-05-15 | 2023-06-13 | 广汽埃安新能源汽车股份有限公司 | Method and device for detecting reference vehicle speed of vehicle steering working condition |
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