CN115892007A - Steering brake method, device, equipment and medium in emergency working conditions - Google Patents

Abstract

The present application provides a steering braking method, device, equipment and medium in an emergency working condition. The method includes: obtaining the road curvature of the current road and the driving state of the vehicle on the current road; if the road curvature is greater than a preset curvature, obtaining the axle load transfer rate of the vehicle according to the driving state; Axle load transfer ratio and the driving state, obtaining expected longitudinal acceleration and expected lateral acceleration; adjusting the opening degree of the brake pedal of the vehicle according to the expected longitudinal acceleration, and adjusting the wheels of the vehicle according to the expected lateral acceleration corner. The method of the present application effectively combines the lateral acceleration and the longitudinal acceleration to perform braking control on the running of the vehicle to achieve an accurate and safe braking effect.

Description

Steering braking method, device, equipment and medium under emergency conditions

Technical Field

The present application relates to the field of vehicle control technology, and in particular to a steering braking method, device, equipment and medium under emergency conditions.

Background Art

With the continuous increase in highway mileage and the increasing amount of cargo carried by commercial vehicles, higher requirements are placed on the safety and reliability of commercial vehicles. In emergency conditions, commercial vehicles need to respond in time to avoid drifting and rollover.

Most of the existing technologies use lateral control methods to control the steering wheel angle while keeping the vehicle speed unchanged to adjust the operating state of the commercial vehicle, or adjust the trajectory of the commercial vehicle by obtaining the current position and target position of the commercial vehicle to achieve lateral tracking control of the commercial vehicle, or adjust the trajectory of the commercial vehicle by calculating the longitudinal safety distance and lane change safety distance of the commercial vehicle; the factors affecting the braking of commercial vehicles considered in these methods are not comprehensive enough, so a more stable, reliable and comprehensive control method is needed.

Summary of the invention

The present application provides a steering braking method, device, equipment and medium under emergency conditions, which are used to solve the problem in the prior art that the braking control method adopts incomplete data, resulting in inaccurate braking control.

In a first aspect, the present application provides a steering braking method under emergency conditions, comprising:

Acquire the road curvature of the current road and the driving status of the vehicle on the current road;

If the road curvature is greater than a preset curvature, obtaining an axle load transfer rate of the vehicle according to the driving state;

Obtaining an expected longitudinal acceleration and an expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state;

The opening degree of the brake pedal of the vehicle is adjusted according to the expected longitudinal acceleration, and the wheel steering angle of the vehicle is adjusted according to the expected lateral acceleration.

In a possible implementation, acquiring the expected longitudinal acceleration and the expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state includes:

If the axle load transfer rate is less than a safety threshold, obtaining the expected lateral acceleration according to the wheel angle and the vehicle speed correction value in the driving state, and obtaining the expected longitudinal acceleration according to the road adhesion;

If the axle load transfer rate is greater than or equal to the safety threshold, the expected lateral acceleration is obtained according to the lateral acceleration in the driving state, the safety threshold and the axle load transfer rate, and the expected longitudinal acceleration is obtained according to the expected lateral acceleration and the ground friction coefficient.

In a possible implementation, acquiring the axle load transfer rate of the vehicle according to the driving state includes:

The axle load transfer rate is obtained according to the vertical loads of the four wheels of the vehicle in the driving state.

In a possible implementation, the obtaining of the expected lateral acceleration according to the wheel angle and the vehicle speed correction value in the driving state, and the obtaining of the expected longitudinal acceleration according to the road adhesion, include:

Obtain the expected lateral force based on the wheel angle and vehicle speed correction value;

Obtaining the expected lateral acceleration according to the expected lateral force and the mass of the vehicle;

The expected longitudinal force is obtained according to the expected lateral force and the friction force of the vehicle, and the expected longitudinal acceleration is obtained according to the expected longitudinal force and the mass of the vehicle.

In a possible implementation, before obtaining the expected lateral force according to the wheel angle and the vehicle speed correction value, the method further includes:

If the longitudinal vehicle speed in the driving state is less than or equal to the safe vehicle speed, obtaining the vehicle speed correction value according to the safe vehicle speed;

If the longitudinal vehicle speed in the driving state is greater than the safe vehicle speed, the longitudinal vehicle speed in the driving state is used as the vehicle speed correction value.

In a possible implementation, obtaining the expected lateral force according to the wheel angle and the vehicle speed correction value includes:

Obtaining a first parameter according to the friction coefficient, the gravitational acceleration and the mass of the vehicle;

Acquire a second parameter according to the wheel angle, the vehicle speed correction value and the mass of the vehicle;

The expected lateral force is obtained according to the ratio of the first parameter to the second parameter.

In a possible implementation, acquiring the expected lateral acceleration according to the lateral acceleration in the driving state, the safety threshold, and the axle load transfer rate includes:

Acquire a ratio of the safety threshold to the axle load transfer rate, and acquire the expected lateral acceleration according to the ratio and the lateral acceleration;

Accordingly, obtaining the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient includes:

Obtaining friction acceleration according to the ground friction coefficient and gravity acceleration;

The expected longitudinal acceleration is obtained according to the friction acceleration and the expected lateral acceleration.

In a second aspect, the present application provides a steering brake device under emergency conditions, comprising:

A first acquisition module, used to acquire the road curvature of the current road and the driving state of the vehicle on the current road;

A judgment module, configured to obtain an axle load transfer rate of the vehicle according to the driving state if the road curvature is greater than a preset curvature;

A second acquisition module, configured to acquire an expected longitudinal acceleration and an expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state;

A processing module is used to adjust the opening of the brake pedal of the vehicle according to the expected longitudinal acceleration, and to adjust the wheel angle of the vehicle according to the expected lateral acceleration.

In a third aspect, the present application provides a steering brake device under emergency conditions, comprising: at least one processor and a memory;

The memory stores computer-executable instructions;

The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs the steering braking method under emergency conditions as described above.

In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the steering braking method under emergency conditions as described above.

The present application provides a steering braking method, device, equipment and medium under emergency conditions, which obtains the road curvature of the current road and the driving state of the vehicle on the current road; if the road curvature is greater than the preset curvature, the axle load transfer rate of the vehicle is obtained according to the driving state; according to the axle load transfer rate of the vehicle and the driving state, the expected longitudinal acceleration and the expected lateral acceleration are obtained; according to the expected longitudinal acceleration, the opening of the brake pedal of the vehicle is adjusted, and the wheel angle of the vehicle is adjusted according to the expected lateral acceleration. In the above method, the lateral acceleration and the longitudinal acceleration are effectively combined to control the braking of the vehicle, so as to achieve an accurate and safe braking effect.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

FIG1 is a schematic diagram of steering braking under emergency conditions proposed in this application;

FIG2 is a flow chart of a steering braking method under emergency conditions proposed in the present application;

FIG3 is a second flow chart of a steering braking method under emergency conditions proposed in the present application;

FIG4 is a flowchart of a steering braking method under emergency conditions proposed in the present application;

FIG5 is a path comparison diagram of a steering braking method under emergency conditions proposed in the present application;

FIG6 is a vehicle speed comparison diagram of a steering braking method under emergency conditions proposed in the present application;

FIG7 is a diagram of a steering brake device under emergency conditions provided by an embodiment of the present invention;

FIG8 is a hardware schematic diagram of a steering brake device under emergency conditions provided by an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

As the mileage of highways continues to grow, the cargo transportation capacity of commercial vehicles is also increasing. The cargo transportation capacity of commercial vehicles also puts forward higher requirements for their safe and reliable driving on the road. In the prior art, when commercial vehicles encounter emergency conditions, reasonable braking methods are required to control vehicle braking. Traditional braking control mostly adopts lateral control, which controls the steering wheel angle without changing the vehicle speed. However, the existing methods consider relatively single factors, so the control effect is increasingly difficult to meet the higher braking requirements of commercial vehicles now.

Therefore, the present application proposes a steering braking method under emergency conditions that can comprehensively consider ground adhesion, lateral acceleration and longitudinal acceleration.

A steering braking method under emergency conditions proposed by the present application is described below in conjunction with FIG. 1 to control the braking of a commercial vehicle under emergency conditions.

Figure 1 is a schematic diagram of steering braking under emergency conditions proposed in this application. As shown in Figure 1, the system includes: a steering wheel 101, a brake pedal 102 and a wheel 103, and also includes a sensor that can monitor the driving curve of the vehicle during driving;

In emergency conditions, the driving curve of the vehicle is obtained through sensors, and the driving data of the vehicle is obtained according to the state perception module inside the vehicle. For example, when encountering a large turn, the vehicle needs to be steered and braked so that the vehicle can drive smoothly or stop smoothly on the curve; wherein, the sensor includes a remote monitoring unit (RMU), which can be used to obtain the driving curve of the vehicle during the driving process, and the curvature of the driving curve is represented by the road curvature. The state perception module inside the vehicle can obtain the vehicle's speed, vertical load and wheel angle.

When the vehicle turns at a certain angle, rollover may occur, which is not conducive to safe driving of the vehicle. Therefore, when the road curvature is greater than the preset curvature, the vehicle's driving state needs to be corrected to ensure that the vehicle can remain in a safe driving state; when the road curvature is less than or equal to the preset curvature, the vehicle's driving state does not need to be corrected, or appropriate deceleration can be performed according to the actual driving conditions. When it is determined that the road curvature is less than or equal to the preset curvature, the vehicle can be controlled in any safe driving state, which is not particularly limited in this embodiment.

When it is determined that the road curvature is greater than the preset curvature, in the process of correcting the vehicle's driving state, it is necessary to obtain the vehicle's driving state on the current road in real time and compare the actual value with the expected value to continuously approach the expected value.

For example, when a vehicle is driving on a curve, it cannot drive at the same speed as it does on a straight road. It needs to obtain whether the vehicle needs to enter a steering and braking state based on the existing road data. If the curvature of the current driving curve does not affect the vehicle's driving, it can continue to drive forward in the original state.

If the curvature of the current vehicle driving curve is too large, that is, the road curvature is too large, which may affect the vehicle driving, the steering wheel 101 can be changed to control the wheel 103 to rotate left and right. After the wheel is rotated left and right, the lateral force of the vehicle will change, thereby causing the lateral acceleration to change. During this change process, the expected lateral acceleration that the vehicle should reach when turning can be obtained in real time. The vehicle is controlled according to the expected lateral acceleration, so that the vehicle driving can gradually meet the safe driving standard.

At the same time, the longitudinal acceleration of the vehicle can be adjusted by changing the opening and closing degree of the brake pedal 102. In this process, it is necessary to obtain the desired longitudinal acceleration while adjusting the opening and closing degree of the brake pedal 102, so that the vehicle's driving can gradually reach the safe driving standard.

In this embodiment, the expected lateral acceleration and expected longitudinal acceleration of the vehicle are updated in real time, and the vehicle steering wheel 101 and brake pedal 102 are adjusted according to the expected lateral acceleration and expected longitudinal acceleration, so that the vehicle travels at the expected acceleration (including the expected lateral acceleration and the expected longitudinal acceleration). The present application comprehensively considers the acceleration conditions of the vehicle in two directions. In the process of meeting the acceleration requirements, since the forces in different directions together will affect the overall driving direction of the vehicle, that is, the road curvature, the vehicle can eventually return to the road curvature requirement that meets the safe driving requirements, and can better achieve the effect of safe braking or slowing down when turning.

The following describes the situation of controlling the braking of a commercial vehicle in the steering braking method under emergency conditions proposed in this application in conjunction with FIG. 2 .

FIG2 is a flow chart of a steering braking method under emergency conditions proposed in this application. As shown in FIG2 , the method includes:

S201. Obtain the road curvature of the current road and the driving status of the vehicle on the current road.

The road curvature can indicate the degree of curvature of the curve encountered by the vehicle. Correspondingly, the vehicle will drive according to the curve, so the road curvature can reflect the turning situation of the vehicle. The greater the road curvature, the greater the turning angle of the vehicle.

The driving state can be represented by the driving parameters of the vehicle under different conditions, including: longitudinal vehicle speed, lateral acceleration, wheel angle and vertical load of the wheel; among which, longitudinal vehicle speed and wheel angle can be used to obtain the expected lateral acceleration, and lateral acceleration can also be used to obtain the expected lateral acceleration. The above different ways of obtaining the expected lateral acceleration can be used in different axle load transfer rates; the expected longitudinal acceleration can be obtained according to the expected lateral acceleration; the vertical load of the wheel is used to obtain the axle load transfer rate. The specific usage of these driving states will be explained in the subsequent steps.

Under actual driving conditions, the sensor can obtain the road curvature in real time until the road curvature returns to the preset curvature, and there is no need to correct the vehicle's driving status.

S202: If the road curvature is greater than a preset curvature, obtaining an axle load transfer rate of the vehicle according to the driving state.

After obtaining the road curvature, a judgment is made. If it is determined that the road curvature is greater than the preset curvature, it is necessary to further obtain the driving state of the vehicle. The driving state includes the force condition of the vehicle. The axle load transfer rate can be obtained based on the force condition of the vehicle; the axle load transfer rate represents the force distribution of the vehicle. A vehicle generally has front wheels and rear wheels. If the force on the front wheels or the rear wheels is too large, it means that the center of gravity of the vehicle has changed and roll may occur. Therefore, the driving state of the vehicle can be adjusted according to the axle load transfer rate.

In the actual driving process of the vehicle, the axle load transfer rate is obtained as follows:

Optionally, the axle load transfer rate is obtained based on the vertical loads of the four wheels of the vehicle in the driving state.

By obtaining the vertical loads of the four wheels of the vehicle in the driving state, the force conditions of the four wheels of the vehicle can be obtained. The specific formula for obtaining the axle load transfer rate LTR according to each vertical load is as follows:

Among them, the axle load transfer rate LTR takes the absolute value; F _l1 is the vertical load of the left front wheel; F _l2 is the vertical load of the left rear wheel; F _r1 is the vertical load of the right front wheel; F _r2 is the vertical load of the right rear wheel.

S203: Obtain expected longitudinal acceleration and expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state.

The axle load transfer rate of a vehicle can be used to indicate whether the vehicle is likely to roll. The larger the value, the more likely it is to roll. When the axle load transfer rate is obtained, a safety threshold can be set for the axle load transfer rate. When the axle load transfer rate is within the safety threshold, the vehicle will not roll, indicating that the vehicle can drive safely. When the axle load transfer rate exceeds the safety threshold, the expected longitudinal acceleration and expected lateral acceleration can be obtained in combination with the obtained driving status. The expected longitudinal acceleration and expected lateral acceleration can be collectively referred to as the expected acceleration. When the expected acceleration meets certain conditions, the vehicle speed and axle load transfer rate will be controlled to achieve a state that allows the vehicle to drive safely.

S204: Adjust the opening of the brake pedal of the vehicle according to the expected longitudinal acceleration, and adjust the wheel angle of the vehicle according to the expected lateral acceleration.

The expected acceleration can be obtained through the actual acceleration. There is a corresponding device on the vehicle that can control the actual acceleration and then adjust the expected acceleration change.

The corresponding devices on the vehicle include a brake pedal that can control the longitudinal acceleration. The opening degree of the brake pedal can change the longitudinal force, that is, change the longitudinal acceleration. The greater the pressure on the brake pedal and the smaller the opening degree, the faster the vehicle decelerates, and vice versa. It also includes a steering wheel that can control the lateral acceleration. The steering wheel can adjust the wheel angle of the vehicle accordingly, and the lateral acceleration also changes accordingly.

In the embodiment of the present application, the curvature of the current road and the driving state of the vehicle on the current road are obtained; if the curvature of the road is greater than the preset curvature, the axle load transfer rate of the vehicle is obtained according to the driving state; according to the axle load transfer rate of the vehicle and the driving state, the expected longitudinal acceleration and the expected lateral acceleration are obtained; according to the expected longitudinal acceleration, the opening of the brake pedal of the vehicle is adjusted, and according to the expected lateral acceleration, the wheel angle of the vehicle is adjusted. In the above method, the lateral acceleration and the longitudinal acceleration are effectively combined to control the braking of the vehicle, so as to achieve an accurate and safe braking effect.

The following further illustrates the method of controlling the braking of a commercial vehicle by means of lateral acceleration and longitudinal acceleration in the steering braking method under emergency conditions proposed in the present application in conjunction with FIGS. 3 to 6 .

FIG3 is a flow chart 2 of a steering braking method under emergency conditions proposed in this application. As shown in FIG3 , the method includes:

S301, determine whether the longitudinal vehicle speed in the driving state is less than or equal to the safe vehicle speed, if so, execute S302, if not, execute S303.

The longitudinal speed can be obtained directly, and the speed correction value is set based on the longitudinal speed and the safe speed. Driving the vehicle at the safe speed can ensure vehicle driving safety; if the longitudinal speed is less than or equal to the safe speed, it means that the vehicle speed is not fast, and the vehicle speed can be appropriately reduced by a small amount; otherwise, it means that the vehicle speed is too fast, and the vehicle speed can be appropriately reduced by a large amount.

The formula for obtaining the safe speed V _safe is as follows:

Wherein, k ₁ =2.33; m is the mass of the vehicle; g is the acceleration due to gravity; k ₂ =9996; δ is the wheel turning angle.

S302. Obtain the vehicle speed correction value according to the safe vehicle speed, and execute S304.

If the longitudinal speed is less than or equal to the safe speed, the vehicle speed can be appropriately reduced slightly, that is, the speed correction value is obtained based on the safe speed. The larger the speed correction value, the smaller the longitudinal acceleration and the slower the vehicle deceleration.

At this time, the formula for the vehicle speed correction value V ₀ is as follows:

V ₀ = V _safe + k ₃

Here, k ₃ =0.00001.

S303: Use the longitudinal vehicle speed in the driving state as the vehicle speed correction value, and execute S304.

If the longitudinal speed is greater than the safe speed, the vehicle speed can be appropriately and significantly reduced, that is, the longitudinal speed that exceeds the safe speed can be directly used as the speed correction value.

S304: If the axle load transfer rate is less than the safety threshold, execute S305 to S309.

After obtaining the vehicle speed correction value required to correct the expected acceleration of the vehicle, the method of obtaining the expected acceleration is divided into two cases based on the axle load transfer rate;

First, when the axle load transfer rate is less than the safety threshold, the adjustment of the expected acceleration can be carried out gradually, and the acceleration (including actual acceleration and expected acceleration) and the change of the expected acceleration can be tracked by sensors at all times.

S305: Obtain a first parameter according to the friction coefficient, the gravitational 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; after the above parameters are obtained, they are used for the first parameter, and the first parameter is used to obtain the expected lateral force.

S306: Obtain a second parameter according to the wheel angle, the vehicle speed correction value and the mass of the vehicle.

The wheel turning angle is the driving state of the current road acquired in advance, and the vehicle speed correction value is acquired in S301 to S303.

S307: Obtain the expected lateral force according to the ratio of the first parameter to the second parameter. The ratio of the first parameter to the second parameter is used as the expected lateral force _Flat1 , and the specific formula is as follows:

F _lat1 = k ₄ /k ₅

为第二参数。Wherein, k ₄ =mu ² g ² is the first parameter; u is the friction coefficient;

is the second parameter.

S308: Obtain the expected lateral acceleration according to the expected lateral force and the mass of the vehicle.

The ratio of the expected lateral force to the mass of the vehicle is taken as the expected lateral acceleration _Flat1 , and the specific formula is as follows:

a _lat1 =F _lat1 /m.

S309: Obtain an expected longitudinal force according to the expected lateral force and the friction force of the vehicle, and obtain the expected longitudinal acceleration according to the expected longitudinal force and the mass of the vehicle.

The specific formula for obtaining the desired longitudinal force F _lon1 is as follows:

The specific formula for obtaining the expected longitudinal acceleration a _lon1 is as follows:

a _lon1 =F _lon1 /m.

In the embodiment of the present application, it is determined whether the longitudinal vehicle speed in the driving state is less than or equal to the safe vehicle speed. If so, the vehicle speed correction value is obtained according to the safe vehicle speed. If not, the longitudinal vehicle speed in the driving state is used as the vehicle speed correction value. If the axle load transfer rate is less than the safety threshold, the first parameter is obtained according to the friction coefficient, the gravitational acceleration and the mass of the vehicle. The second parameter is obtained according to the wheel angle, the vehicle speed correction value and the mass of the vehicle. The expected lateral force is obtained according to the ratio of the first parameter to the second parameter. The expected lateral acceleration is obtained according to the expected lateral force and the mass of the vehicle. The expected longitudinal force is obtained according to the expected lateral force and the friction force of the vehicle, and the expected longitudinal acceleration is obtained according to the expected longitudinal force and the mass of the vehicle. In the above method, when the axle load transfer rate is less than the safety threshold, the expected lateral acceleration and the expected longitudinal acceleration that can be used as the basis for braking are obtained through parameters such as the wheel speed, the vehicle correction value and the friction coefficient, and the expected acceleration is continuously updated by adjusting the vehicle correction value in real time, so as to adjust the appropriate braking speed at all times, thereby ensuring the accuracy and safety of the vehicle's driving route.

FIG4 is a flowchart of a steering braking method under emergency conditions proposed in this application. As shown in FIG4 , the method includes:

S401. If the axle load transfer rate is greater than or equal to the safety threshold, execute S402 to S403.

After obtaining the vehicle speed correction value required to correct the expected acceleration of the vehicle, the method of obtaining the expected acceleration is divided into two cases based on the axle load transfer rate;

Secondly, when the axle load transfer rate is greater than or equal to the safety threshold, the adjustment of the expected acceleration can be carried out by directly decelerating the vehicle through the expected acceleration to control the braking of the vehicle.

S402: Obtain a ratio of the safety threshold to the axle load transfer rate, and obtain the expected lateral acceleration according to the ratio and the lateral acceleration.

The ratio of the safety threshold to the axle load transfer rate is used as the proportional coefficient, and the expected lateral acceleration a _lat2 is obtained according to the lateral acceleration. The specific formula is as follows:

Among them, F _safe is the safety threshold; a _y is the lateral acceleration, and the lateral acceleration is the actual lateral acceleration of the vehicle on the current road.

S403: Obtain friction acceleration according to the ground friction coefficient and gravity acceleration.

The specific formula for obtaining the friction acceleration a _u is as follows:

a _u =ug ² .

S404: Obtain the expected longitudinal acceleration according to the friction acceleration and the expected lateral acceleration.

According to the friction acceleration and the expected lateral acceleration, the specific formula for obtaining the expected longitudinal acceleration a _lon2 is as follows:

In an embodiment of the present application, if the axle load transfer rate is greater than or equal to the safety threshold, the ratio of the safety threshold to the axle load transfer rate is obtained, and the expected lateral acceleration is obtained based on the ratio and the lateral acceleration. The friction acceleration is obtained based on the ground friction coefficient and the gravity acceleration. The expected longitudinal acceleration is obtained based on the friction acceleration and the expected lateral acceleration. In the above method, when the axle load transfer rate is less than or equal to the safety threshold, the parameters such as the lateral acceleration, the safety threshold and the axle load transfer rate are used to obtain the expected lateral acceleration and the expected longitudinal acceleration that can be used as the basis for braking, and the expected acceleration adjusts the vehicle to ensure the accuracy and safety of the vehicle's driving route.

FIG5 is a path comparison diagram of a steering braking method under emergency conditions proposed by the present application. As shown in FIG5, the method of the present invention continuously obtains the driving trajectory of the vehicle while tracking the acceleration, and also compares it with the actual trajectory of the road where the vehicle is located (reference path, which can correspond to the road curvature) and the proportional-integral-differential control method in the prior art; it can be seen from FIG5 that the present invention is closer to the actual trajectory, and the prior art still gradually deviates from the actual track during the braking process, and has a tendency to get farther and farther, so the accuracy of correcting the driving trajectory is lower than that of the present invention, and the control accuracy of the present invention is higher.

Figure 6 is a vehicle speed comparison diagram of a steering braking method under emergency conditions proposed in this application. As shown in Figure 6, the vehicle speed change of the method of the present invention during braking is compared with the vehicle speed change of the proportional-integral-differential control method in the prior art; as can be seen from Figure 6, the present invention can achieve a more obvious deceleration effect while ensuring safe driving, and the vehicle speed change is more flexible.

FIG7 is a diagram of a steering brake device under emergency conditions provided by an embodiment of the present invention. As shown in FIG7 , the device includes: a first acquisition module 701, a judgment module 702, a second acquisition module 703 and a processing module 704;

The first acquisition module 701 is used to acquire the road curvature of the current road and the driving state of the vehicle on the current road.

The judgment module 702 is used to obtain the axle load transfer rate of the vehicle according to the driving state if the road curvature is greater than a preset curvature.

The second acquisition module 703 is used to acquire the expected longitudinal acceleration and the expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state.

The second acquisition module 703 is further configured to acquire the expected lateral acceleration according to the wheel angle and the vehicle speed correction value in the driving state, and acquire the expected longitudinal acceleration according to the road adhesion if the axle load transfer rate is less than the safety threshold;

If the axle load transfer rate is greater than or equal to the safety threshold, the expected lateral acceleration is obtained according to the lateral acceleration in the driving state, the safety threshold and the axle load transfer rate, and the expected longitudinal acceleration is obtained according to the expected lateral acceleration and the ground friction coefficient.

The second acquisition module 703 is further used to acquire the expected lateral force according to the wheel angle and the vehicle speed correction value;

Obtaining the expected lateral acceleration according to the expected lateral force and the mass of the vehicle;

The expected longitudinal force is obtained according to the expected lateral force and the friction force of the vehicle, and the expected longitudinal acceleration is obtained according to the expected longitudinal force and the mass of the vehicle.

The second acquisition module 703 is further configured to acquire the vehicle speed correction value according to the safe vehicle speed if the longitudinal vehicle speed in the driving state is less than or equal to the safe vehicle speed;

If the longitudinal vehicle speed in the driving state is greater than the safe vehicle speed, the longitudinal vehicle speed in the driving state is used as the vehicle speed correction value.

The second acquisition module 703 is further used to acquire the first parameter according to the friction coefficient, the gravitational acceleration and the mass of the vehicle;

Acquire a second parameter according to the wheel angle, the vehicle speed correction value and the mass of the vehicle;

The expected lateral force is obtained according to the ratio of the first parameter to the second parameter.

The second acquisition module 703 is further used to acquire the expected lateral acceleration according to the lateral acceleration in the driving state, the safety threshold and the axle load transfer rate, including:

Acquire a ratio of the safety threshold to the axle load transfer rate, and acquire the expected lateral acceleration according to the ratio and the lateral acceleration;

Accordingly, obtaining the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient includes:

Obtaining friction acceleration according to the ground friction coefficient and gravity acceleration;

The expected longitudinal acceleration is obtained according to the friction acceleration and the expected lateral acceleration.

The processing module 704 is configured to adjust the opening of the brake pedal of the vehicle according to the expected longitudinal acceleration, and adjust the wheel angle of the vehicle according to the expected lateral acceleration.

The present application also provides a steering brake device under emergency conditions, comprising: at least one processor and a memory;

The memory stores computer-executable instructions;

The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs a steering braking method under emergency conditions.

FIG8 is a hardware schematic diagram of a steering brake device under emergency conditions provided by an embodiment of the present invention. As shown in FIG8 , the steering brake device under emergency conditions 80 provided by this embodiment includes: at least one processor 801 and a memory 802. The device 80 also includes a communication component 803. The processor 801, the memory 802 and the communication component 803 are connected via a bus 804.

In a specific implementation process, at least one processor 801 executes the computer-executable instructions stored in the memory 802, so that at least one processor 801 executes the steering braking method under the above emergency condition.

The specific implementation process of the processor 801 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

In the embodiment shown in FIG. 8 above, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (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, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus.

The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the steering braking method under emergency conditions as described above is implemented.

The computer-readable storage medium mentioned above can be implemented by any type of volatile or non-volatile storage device or a 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 disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (Application Specific Integrated Circuits, referred to as ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

The division of the units is only a logical function division, and there may be other divisions in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, which may be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk, etc., various media that can store program codes.

Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variation, use or adaptation of the present invention, which follows the general principles of the present invention and includes common knowledge or customary technical means in the art not disclosed by the present invention, is not limited to the precise structure described above and shown in the drawings, and can be variously modified and changed without departing from the scope thereof. The scope of the present 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.

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