Steering brake method, apparatus, device, and medium in emergency working condition

Abstract

The application provides a steering braking method, device, equipment and medium under an emergency working condition. The method comprises the following steps: acquiring a road curvature of a current road and a driving state of a vehicle on the current road; if the road curvature is greater than a preset curvature, acquiring an axle load transfer rate of the vehicle according to the driving state; acquiring a desired longitudinal acceleration and a desired lateral acceleration according to the axle load transfer rate of the vehicle and the driving state; 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. The method effectively combines the lateral acceleration and the longitudinal acceleration to brake the vehicle, and achieves an accurate and safe braking effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle control, and in particular to a steering braking method, device, equipment and medium under emergency working conditions. BACKGROUND

[0002] With the continuous growth of highway mileage and the continuous increase of cargo transportation capacity carried by commercial vehicles, higher requirements are put forward for the safety and reliability of commercial vehicles. Under emergency working conditions, commercial vehicles need to respond in time to avoid drifting and rollover.

[0003] Most of the prior art adopts a lateral control method to control the steering wheel angle under the condition that the vehicle speed is constant, to adjust the running state of the commercial vehicle, or to adjust the trajectory of the commercial vehicle by obtaining the current position and target position of the commercial vehicle, to realize lateral tracking control of the commercial vehicle, or to adjust the trajectory of the commercial vehicle by calculating the longitudinal safety distance and lane changing safety distance of the commercial vehicle; the factors affecting the braking of the commercial vehicle considered in these methods are not comprehensive enough, so a more stable and reliable and comprehensive control method is needed. SUMMARY

[0004] The present application provides a steering braking method, device, equipment and medium under emergency working conditions to solve the problem that the braking control method in the prior art uses insufficient data, resulting in inaccurate braking control.

[0005] In a first aspect, the present application provides a steering braking method under emergency working conditions, comprising:

[0006] obtaining the road curvature of the current road and the driving state of the vehicle on the current road;

[0007] if the road curvature is greater than a preset curvature, obtaining the axle load transfer rate of the vehicle according to the driving state;

[0008] obtaining the expected longitudinal acceleration and the expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state;

[0009] adjusting the opening degree of the brake pedal of the vehicle according to the expected longitudinal acceleration, and adjusting the wheel angle of the vehicle according to the expected lateral acceleration.

[0010] In a possible implementation, the step of obtaining the expected longitudinal acceleration and the expected lateral acceleration according to the axle load transfer rate of the vehicle and the driving state comprises:

[0011] 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;

[0012] If the axle load transfer rate is greater than or equal to a safety threshold, the expected lateral acceleration is obtained according to a 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 a ground friction coefficient.

[0013] In a possible implementation, the axle load transfer rate of the vehicle is obtained according to the driving state, including:

[0014] The axle load transfer rate is obtained according to vertical loads of four wheels of the vehicle in the driving state.

[0015] In a possible implementation, the expected lateral acceleration is obtained according to the wheel angle and the vehicle speed correction value in the driving state, and the expected longitudinal acceleration is obtained according to a road adhesion, including:

[0016] The expected lateral force is obtained according to the wheel angle and the vehicle speed correction value;

[0017] The expected lateral acceleration is obtained according to the expected lateral force and a mass of the vehicle;

[0018] The expected longitudinal force is obtained according to the expected lateral force and a friction force of the vehicle, and the expected longitudinal acceleration is obtained according to the expected longitudinal force and the mass of the vehicle.

[0019] In a possible implementation, before the expected lateral force is obtained according to the wheel angle and the vehicle speed correction value, the method further includes:

[0020] If the longitudinal vehicle speed in the driving state is less than or equal to a safety vehicle speed, the vehicle speed correction value is obtained according to the safety vehicle speed;

[0021] If the longitudinal vehicle speed in the driving state is greater than the safety vehicle speed, the longitudinal vehicle speed in the driving state is taken as the vehicle speed correction value.

[0022] In a possible implementation, the expected lateral force is obtained according to the wheel angle and the vehicle speed correction value, including:

[0023] A first parameter is obtained according to a friction coefficient, a gravitational acceleration and a mass of the vehicle;

[0024] A second parameter is obtained according to the wheel angle, the vehicle speed correction value and the mass of the vehicle;

[0025] The expected lateral force is obtained according to a ratio of the first parameter and the second parameter.

[0026] In a possible implementation, the obtaining of the expected lateral acceleration according to the lateral acceleration in the driving state, the safety threshold and the axle load transfer rate comprises:

[0027] 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;

[0028] Correspondingly, the obtaining of the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient comprises:

[0029] obtaining a friction acceleration according to the ground friction coefficient and the gravitational acceleration;

[0030] obtaining the expected longitudinal acceleration according to the friction acceleration and the expected lateral acceleration.

[0031] In a second aspect, the present application provides a steering brake device in an emergency working condition, comprising:

[0032] a first obtaining module, configured to obtain a road curvature of a current road and a driving state of a vehicle on the current road;

[0033] a judging 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;

[0034] a second obtaining module, 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;

[0035] a processing module, configured to adjust an opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration, and adjust a wheel rotation angle of the vehicle according to the expected lateral acceleration.

[0036] In a third aspect, the present application provides a steering brake device in an emergency working condition, comprising at least one processor and a memory;

[0037] the memory stores computer execution instructions;

[0038] the at least one processor executes the computer execution instructions stored in the memory, so that the at least one processor executes the steering brake method in an emergency working condition as described above.

[0039] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the steering brake method in an emergency working condition as described above.

[0040] The application provides a steering braking method, device, equipment and medium under an emergency working condition, acquires a road curvature of a current road and a driving state of a vehicle on the current road; if the road curvature is greater than a preset curvature, acquires an axle load transfer rate of the vehicle according to the driving state; acquires a desired longitudinal acceleration and a desired lateral acceleration according to the axle load transfer rate of the vehicle and the driving state; adjusts an opening degree of a brake pedal of the vehicle according to the desired longitudinal acceleration, and adjusts a wheel rotation angle of the vehicle according to the desired lateral acceleration. In the above method, the lateral acceleration and the longitudinal acceleration are effectively combined to brake control the vehicle driving, and an accurate and safe braking effect is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0042] Figure 1 A steering braking schematic diagram under an emergency working condition is provided for the present application.

[0043] Figure 2 A flow of a steering braking method under an emergency working condition is provided for the present application. Figure 1 ;

[0044] Figure 3 A flow of a steering braking method under an emergency working condition is provided for the present application. Figure 2 ;

[0045] Figure 4 A flow of a steering braking method under an emergency working condition is provided for the present application. Figure 3 ;

[0046] Figure 5 A path comparison diagram of a steering braking method under an emergency working condition is provided for the present application.

[0047] Figure 6 A vehicle speed comparison diagram of a steering braking method under an emergency working condition is provided for the present application.

[0048] Figure 7 A steering braking device diagram under an emergency working condition is provided for the embodiments of the present application.

[0049] Figure 8 A hardware schematic diagram of a steering braking device under an emergency working condition is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0050] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] With the continuous growth of highway mileage, the carrying capacity of commercial vehicles is also increasing, and the carrying capacity of commercial vehicles also puts forward higher requirements for safe and reliable driving on the road. In the prior art, the commercial vehicle needs to be reasonably controlled by braking in emergency working conditions, and the traditional braking control mostly adopts transverse control to control the steering wheel angle under the condition of constant vehicle speed. However, the existing method considers single factor, so the control effect is more and more difficult to meet the higher braking requirements of commercial vehicles.

[0052] Therefore, the present application provides a steering braking method in emergency working conditions which can comprehensively consider the ground adhesion, lateral acceleration and longitudinal acceleration.

[0053] The following will be combined Figure 1 to describe a steering braking method in emergency working conditions provided by the present application to control the braking of commercial vehicles in emergency working conditions.

[0054] Figure 1 The steering braking in emergency working conditions provided by the present application is shown in the schematic diagram. As Figure 1 shown, the system includes a steering wheel 101, a brake pedal 102 and a wheel 103, and further includes a sensor which can monitor the driving curve in the driving process of the vehicle;

[0055] In emergency working conditions, the driving curve in the driving process of the vehicle is obtained by the sensor, and the driving data of the vehicle is obtained according to the state perception module inside the vehicle, for example, in the state of encountering a large turn, the steering braking of the vehicle is needed to make the vehicle drive smoothly or stop smoothly on the curve; wherein the sensor includes a remote monitoring unit (Remote Monitoring Unit, RMU), which can be used to obtain the driving curve in the driving process of the vehicle, and the bending degree of the driving curve is represented by the road curvature, and the state perception module inside the vehicle can obtain the speed, vertical load and wheel angle of the vehicle.

[0056] When the turning angle of the vehicle reaches a certain degree, rollover and other situations may occur, which is not conducive to the safe driving of the vehicle. Therefore, when the road curvature is greater than the preset curvature, the driving state of the vehicle 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 driving state of the vehicle can not be corrected, or appropriate deceleration can be made according to the actual driving situation. In the case of determining that the road curvature is less than or equal to the preset curvature, the vehicle control can be performed in any safe driving state, which is not particularly limited in the embodiment.

[0057] In the case of determining that the road curvature is greater than the preset curvature, the driving state of the vehicle needs to be corrected in real time during the process, and the actual value is compared with the expected value to constantly approach the expected value.

[0058] For example, when the vehicle is driving on a curve, the vehicle cannot use the driving speed on a straight road to drive, and needs to determine whether the vehicle needs to enter a turning braking state according to the existing road data. If the degree of curvature of the current driving curve does not reach the degree that affects the driving of the vehicle, the vehicle can continue to drive according to the original driving state.

[0059] If the degree of curvature of the current driving curve of the vehicle is too large, that is, the road curvature is too large, which may affect the driving of the vehicle, the steering wheel 101 can be changed to control the left and right rotation of the wheels 103. After the wheels 103 are rotated left and right, the lateral force of the vehicle changes, so that the lateral acceleration changes. In this process, the expected lateral acceleration that the vehicle should reach when turning can be obtained in real time, and the vehicle can be controlled according to the expected lateral acceleration, so that the driving of the vehicle gradually reaches the safe driving standard.

[0060] At the same time, the opening and closing degree of the brake pedal 102 can be changed to adjust the longitudinal acceleration of the vehicle. In this process, the expected longitudinal acceleration needs to be obtained while adjusting the opening and closing degree of the brake pedal 102, so that the driving of the vehicle gradually reaches the safe driving standard.

[0061] 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 drives in the expected acceleration (including the expected lateral acceleration and the expected longitudinal acceleration). The application comprehensively considers the acceleration conditions of the vehicle in two directions. In the process of meeting the acceleration requirements, the forces in different directions combine to affect the overall driving direction of the vehicle, that is, the road curvature is affected, so that the vehicle can finally recover to meet the road curvature requirements of safe driving, and the effect of safe braking or slow driving can be better achieved when turning.

[0062] The following will be described in combination withFigure 2 The application discloses a method for controlling braking of a commercial vehicle in an emergency working condition.

[0063] Figure 2 A flowchart of the method for controlling braking of a commercial vehicle in an emergency working condition Figure 1 As shown in Figure 2 , the method comprises the following steps.

[0064] S201, acquiring a road curvature of a current road and a driving state of a vehicle on the current road.

[0065] The road curvature of the road can represent the bending degree of a curve encountered by the vehicle, and correspondingly, the vehicle drives according to the curve, so that the road curvature can reflect the turning condition of the vehicle, and the greater the road curvature, the greater the turning angle of the vehicle.

[0066] The driving state can be represented by driving parameters of the vehicle in different conditions, including a longitudinal vehicle speed, a lateral acceleration, a wheel rotation angle and a vertical load of a wheel; wherein the longitudinal vehicle speed and the wheel rotation angle can be used to acquire an expected lateral acceleration, and the lateral acceleration can also be used to acquire the expected lateral acceleration, and the above different ways of acquiring the expected lateral acceleration can be used in different axle load transfer rate conditions; an expected longitudinal acceleration can be obtained according to the expected lateral acceleration; and the vertical load of the wheel is used to acquire the axle load transfer rate. The driving state will be described in detail in the subsequent steps.

[0067] In actual driving conditions, the sensor can acquire the road curvature of the road in real time, and until the road curvature returns to a preset curvature, the driving state of the vehicle can not be corrected.

[0068] S202, if the road curvature is greater than a preset curvature, acquiring an axle load transfer rate of the vehicle according to the driving state.

[0069] After the road curvature is acquired, it is determined that the road curvature is greater than the preset curvature, and the driving state of the vehicle needs to be further acquired, which includes the force condition of the vehicle, and the axle load transfer rate can be acquired according to the force condition of the vehicle; wherein the axle load transfer rate represents the force distribution of the vehicle, and the vehicle generally has front wheels and rear wheels, if the force of the front wheels or the rear wheels is too large, it indicates that the center of gravity of the vehicle changes, and the vehicle may be inclined, so the driving state of the vehicle can be adjusted according to the axle load transfer rate.

[0070] In the actual driving process of the vehicle, the axle load transfer rate can be acquired in the following manner.

[0071] Optionally, the axle load transfer rate is acquired according to the vertical loads of four wheels of the vehicle in the driving state.

[0072] By acquiring 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 acquired, and a specific formula of the axle load transfer rate LTR according to each vertical load is as follows:

[0073]

[0074] LTR = | Fx / (Ff + Fr) | 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.

[0075] S203, acquiring a desired longitudinal acceleration and a desired lateral acceleration according to the axle load transfer rate of the vehicle and the driving state.

[0076] The axle load transfer rate of the vehicle can be used to indicate whether the vehicle is likely to roll, and the greater the value is, the more likely the vehicle is to roll. In the case of acquiring the axle load transfer rate, a safety threshold can be set for the axle load transfer rate. When the axle load transfer rate is within the safety threshold range, the vehicle will not roll, indicating that the vehicle can safely drive. When the axle load transfer rate exceeds the safety threshold, the desired longitudinal acceleration and the desired lateral acceleration can be acquired in combination with the acquired driving state. The desired longitudinal acceleration and the desired lateral acceleration can be collectively referred to as a desired acceleration. When the desired acceleration meets certain conditions, the speed and the axle load transfer rate of the vehicle will be controlled, achieving a state in which the vehicle can safely drive.

[0077] S204, adjusting the opening degree 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.

[0078] The desired acceleration can be acquired by the actual acceleration, and corresponding devices on the vehicle can control the actual acceleration to adjust the desired acceleration.

[0079] The corresponding devices on the vehicle include a brake pedal that can control the longitudinal acceleration, and the opening degree of the brake pedal can change the longitudinal force, i.e., the longitudinal acceleration. The greater the pressure on the brake pedal, the smaller the opening degree, and the faster the vehicle decelerates. Conversely, the slower the vehicle decelerates. The corresponding devices also include a steering wheel that can control the lateral acceleration, and the steering wheel can adjust the wheel angle of the vehicle, and correspondingly, the lateral acceleration also changes.

[0080] In the embodiment of the present application, the road curvature of the current road and the driving state of the vehicle on the current road are acquired; if the road curvature is greater than a preset curvature, the axle load transfer rate of the vehicle is acquired according to the driving state; the expected longitudinal acceleration and the expected lateral acceleration are acquired according to the axle load transfer rate of the vehicle and the driving state; the opening of the brake pedal of the vehicle is adjusted according to the expected longitudinal acceleration, 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 that the accurate and safe braking effect is achieved.

[0081] The above method will be described below in combination with Figures 3 to 6 The method for controlling the braking of the commercial vehicle through the lateral acceleration and the longitudinal acceleration in the emergency working condition of the present application will be further described.

[0082] Figure 3 The flow of the method for controlling the braking of the commercial vehicle through the lateral acceleration and the longitudinal acceleration in the emergency working condition of the present application Figure 2 As shown in Figure 3 , the method comprises the following steps.

[0083] S301, it is judged whether the longitudinal vehicle speed in the driving state is less than or equal to a safe vehicle speed, if yes, S302 is executed, if not, S303 is executed.

[0084] The longitudinal vehicle speed can be directly acquired, and the vehicle speed correction value is set according to the size of the longitudinal vehicle speed and the size of the safe vehicle speed. The vehicle can be driven at the safe vehicle speed to ensure the driving safety of the vehicle. If the longitudinal vehicle speed is less than or equal to the safe vehicle speed, it indicates that the driving speed of the vehicle is not fast, and the speed of the vehicle can be appropriately reduced in a small range. Otherwise, it indicates that the driving speed of the vehicle is too fast, and the speed of the vehicle can be appropriately reduced in a large range.

[0085] The safe vehicle speed V safe is acquired according to the following formula:

[0086]

[0087] Wherein, k1=2.33; m is the mass of the whole vehicle; g is the acceleration of gravity; k2=9996; and δ is the wheel angle.

[0088] S302, the vehicle speed correction value is acquired according to the safe vehicle speed, and S304 is executed.

[0089] If the longitudinal vehicle speed is less than or equal to the safe vehicle speed, the speed of the vehicle can be appropriately reduced in a small range, that is, the vehicle speed correction value is acquired according to the safe vehicle speed. The greater the vehicle speed correction value is, the smaller the longitudinal acceleration is, and the slower the vehicle is reduced.

[0090] At this time, the formula of the vehicle speed correction value V0 is as follows:

[0091] V0 = V safe +k3

[0092] wherein k3 = 0.00001.

[0093] S303, the longitudinal vehicle speed in the driving state is taken as the vehicle speed correction value, and S304 is performed.

[0094] If the longitudinal vehicle speed is greater than the safe vehicle speed, the vehicle speed can be appropriately greatly reduced, that is, the longitudinal vehicle speed exceeding the safe vehicle speed is directly taken as the vehicle speed correction value.

[0095] S304, if the axle load transfer rate is less than the safety threshold, S305 to S309 are performed.

[0096] After obtaining the vehicle speed correction value required to correct the expected acceleration of the vehicle, the way to obtain the expected acceleration is divided into two cases according to the axle load transfer rate.

[0097] First, in the case where the axle load transfer rate is less than the safety threshold, the adjustment of the expected acceleration can be gradually performed, and the changes of the acceleration (including the actual acceleration and the expected acceleration) and the expected acceleration can be tracked at any time through the sensor.

[0098] S305, a first parameter is obtained according to the friction coefficient, the gravitational acceleration and the mass of the vehicle.

[0099] The friction coefficient can be directly obtained through the road type and the wheel type, and the gravitational acceleration and the mass of the vehicle can also be directly obtained; the above parameters are used to obtain the first parameter, which is used to obtain the expected lateral force.

[0100] S306, a second parameter is obtained according to the wheel angle, the vehicle speed correction value and the mass of the vehicle.

[0101] The wheel angle is the driving state of the current road obtained in advance, and the vehicle speed correction value is obtained in S301 to S303.

[0102] S307, the expected lateral force is obtained according to the ratio of the first parameter and the second parameter. The ratio of the first parameter and the second parameter is taken as the expected lateral force F lat1 , and the specific formula is as follows:

[0103] F lat1 = k4 / k5

[0104] wherein k4 = mu 2 g 2 , u is the friction coefficient, and g is the gravitational acceleration; is the second parameter.

[0105] S308, obtaining the expected lateral acceleration according to the expected lateral force and the mass of the vehicle.

[0106] The ratio of the expected lateral force and the mass of the vehicle is taken as the expected lateral acceleration F lat1 , and the specific formula is as follows:

[0107] a lat1 =F lat1 / m.

[0108] S309, obtaining the expected longitudinal force according to the expected lateral force and the friction of the vehicle, and obtaining the expected longitudinal acceleration according to the expected longitudinal force and the mass of the vehicle.

[0109] The specific formula for obtaining the expected longitudinal force F lon1 is as follows:

[0110]

[0111] The specific formula for obtaining the expected longitudinal acceleration a lon1 is as follows:

[0112] a lon1 =F lon1 / m.

[0113] In the embodiments of the present application, it is judged whether the longitudinal vehicle speed in the driving state is less than or equal to a safe vehicle speed, if yes, the vehicle speed correction value is obtained according to the safe vehicle speed, if not, the longitudinal vehicle speed in the driving state is taken as the vehicle speed correction value. If the axle load transfer rate is less than a safe threshold, a first parameter is obtained according to the friction coefficient, the acceleration of gravity and the mass of the vehicle. A second parameter is obtained according to the wheel rotation 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 and 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 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 safe threshold, the expected lateral acceleration and the expected longitudinal acceleration which can be used as the basis for braking are obtained through parameters such as wheel rotation speed, vehicle correction value and friction coefficient, and the expected acceleration is constantly updated by adjusting the vehicle correction value in real time, so that the appropriate braking speed is adjusted at any time, and the accuracy and safety of the driving route of the vehicle are ensured.

[0114] Figure 4 A flowchart of a steering braking method in an emergency working condition is provided for the present application Figure 3 . As shown in Figure 4 , the method comprises:

[0115] S401, if the axle load transfer rate is greater than or equal to a safety threshold, then S402 to S403 are performed.

[0116] After obtaining the vehicle speed correction value required to correct the desired vehicle acceleration, the manner of obtaining the desired acceleration is divided into two cases based on the axle load transfer rate.

[0117] Second, in the case where the axle load transfer rate is greater than or equal to the safety threshold, the adjustment of the desired acceleration can be controlled by directly reducing the vehicle braking through the desired acceleration.

[0118] S402, obtain the ratio of the safety threshold to the axle load transfer rate, and obtain the desired lateral acceleration based on the ratio and the lateral acceleration.

[0119] The ratio of the safety threshold to the axle load transfer rate is used as a proportional coefficient to obtain the desired lateral acceleration a lat2 , the specific formula is as follows:

[0120]

[0121] Where F safe is the safety threshold; a y is the lateral acceleration, which is the actual lateral acceleration of the vehicle driving on the current road.

[0122] S403, obtain the friction acceleration based on the ground friction coefficient and the gravitational acceleration.

[0123] The specific formula for obtaining the friction acceleration a u is as follows:

[0124] a u = ug 2 .

[0125] S404, obtain the desired longitudinal acceleration based on the friction acceleration and the desired lateral acceleration.

[0126] The specific formula for obtaining the desired longitudinal acceleration a lon2 based on the friction acceleration and the desired lateral acceleration is as follows:

[0127]

[0128] In the embodiment of the present application, if the axle load transfer rate is greater than or equal to a safety threshold, the 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. The friction acceleration is obtained according to the ground friction coefficient and the gravitational acceleration. The expected longitudinal acceleration is obtained according to 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 lateral acceleration, the safety threshold and the axle load transfer rate are obtained, and the expected lateral acceleration and the expected longitudinal acceleration which can be used as braking basis are obtained, and the expected acceleration adjusts the vehicle, thereby ensuring the accuracy and safety of the driving route of the vehicle.

[0129] Figure 5 A path comparison diagram of a steering braking method in an emergency working condition is provided for the present application. Figure 5 As shown in the figure, the method of the present application not only tracks the acceleration, but also constantly obtains the driving trajectory of the vehicle, and compares with the actual trajectory of the road (reference path, which can correspond to the road curvature) and the proportional-integral-derivative control method in the prior art. Figure 5 It can be seen that the present application is closer to the actual trajectory, and the prior art gradually deviates from the actual trajectory during braking, and has a trend of becoming more and more far away, so the accuracy of correcting the driving trajectory is relatively lower, and the control accuracy of the present application is higher.

[0130] Figure 6 A vehicle speed comparison diagram of a steering braking method in an emergency working condition is provided for the present application. Figure 6 As shown in the figure, the vehicle speed change during braking of the method of the present application is compared with the vehicle speed change of the proportional-integral-derivative control method in the prior art. Figure 6 It can be seen that the present application can achieve more obvious deceleration effect under the condition of ensuring safe driving, and the vehicle speed change is more flexible.

[0131] Figure 7 A steering braking device diagram in an emergency working condition is provided for the embodiment of the present application. Figure 7 As shown in the figure, the device comprises a first obtaining module 701, a judging module 702, a second obtaining module 703 and a processing module 704.

[0132] The first obtaining module 701 is configured to obtain the road curvature of the current road and the driving state of the vehicle on the current road.

[0133] The judging module 702 is configured 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.

[0134] The second obtaining module 703 is configured to obtain a desired longitudinal acceleration and a desired lateral acceleration according to the axle load transfer ratio of the vehicle and the driving state.

[0135] The second obtaining module 703 is further configured to, if the axle load transfer ratio is less than a safety threshold, obtain the desired lateral acceleration according to a wheel steering angle and a vehicle speed correction value in the driving state, and obtain the desired longitudinal acceleration according to a road adhesion force.

[0136] If the axle load transfer ratio is greater than or equal to the safety threshold, the second obtaining module 703 is configured to obtain the desired lateral acceleration according to a lateral acceleration, the safety threshold and the axle load transfer ratio in the driving state, and obtain the desired longitudinal acceleration according to the desired lateral acceleration and a ground friction coefficient.

[0137] The second obtaining module 703 is further configured to obtain a desired lateral force according to a wheel steering angle and a vehicle speed correction value.

[0138] The second obtaining module 703 is further configured to obtain the desired lateral acceleration according to the desired lateral force and a mass of the vehicle.

[0139] The second obtaining module 703 is further configured to obtain a desired longitudinal force according to the desired lateral force and a friction force of the vehicle, and obtain the desired longitudinal acceleration according to the desired longitudinal force and the mass of the vehicle.

[0140] The second obtaining module 703 is further configured to, if a longitudinal vehicle speed in the driving state is less than or equal to a safety vehicle speed, obtain the vehicle speed correction value according to the safety vehicle speed.

[0141] If the longitudinal vehicle speed in the driving state is greater than the safety vehicle speed, the second obtaining module 703 is configured to take the longitudinal vehicle speed in the driving state as the vehicle speed correction value.

[0142] The second obtaining module 703 is further configured to obtain a first parameter according to a friction coefficient, a gravitational acceleration and a mass of the vehicle.

[0143] The second obtaining module 703 is further configured to obtain a second parameter according to a wheel steering angle, a vehicle speed correction value and the mass of the vehicle.

[0144] The second obtaining module 703 is further configured to obtain the desired lateral force according to a ratio of the first parameter and the second parameter.

[0145] The second obtaining module 703 is further configured to obtain the desired lateral acceleration according to a lateral acceleration, the safety threshold and the axle load transfer ratio in the driving state, including:

[0146] The second obtaining module 703 is further configured to obtain a ratio of the safety threshold and the axle load transfer ratio, and obtain the desired lateral acceleration according to the ratio and the lateral acceleration.

[0147] Correspondingly, the obtaining the expected longitudinal acceleration according to the expected lateral acceleration and the ground friction coefficient comprises:

[0148] obtaining a friction acceleration according to the ground friction coefficient and the gravity acceleration;

[0149] obtaining the expected longitudinal acceleration according to the friction acceleration and the expected lateral acceleration.

[0150] The processing module 704 is configured to adjust an opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration, and adjust a wheel rotation angle of the vehicle according to the expected lateral acceleration.

[0151] The application also provides a steering braking device under an emergency working condition, comprising at least one processor and a memory.

[0152] The memory stores computer-executed instructions.

[0153] The at least one processor executes the computer-executed instructions stored in the memory, so that the at least one processor executes a steering braking method under an emergency working condition.

[0154] Figure 8 A hardware schematic diagram of the steering braking device under an emergency working condition provided by the embodiment of the application is shown in FIG. 1. Figure 8 As shown in FIG. 1, the steering braking device 80 under an emergency working condition provided by the embodiment of the application comprises 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 component 803 are connected through a bus 804.

[0155] In the specific implementation process, the at least one processor 801 executes the computer-executed instructions stored in the memory 802, so that the at least one processor 801 executes the steering braking method under an emergency working condition as described above.

[0156] The specific implementation process of the processor 801 can refer to the method embodiments described above, which has similar implementation principles and technical effects, and will not be described here again.

[0157] In the above Figure 8In the illustrated embodiment, it is to be understood that the processor can be a central processing unit (CPU), and can also be other general purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), etc. The general purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the disclosed method can be directly embodied as hardware processor execution, or a combination of hardware and software modules in the processor.

[0158] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), such as at least one disk memory.

[0159] The bus can be an industry standard architecture (ISA) bus, a peripheral component (PCI) bus, or an extended industry standard architecture (EISA) bus, etc. The bus can 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 does not limit to only one bus or one type of bus.

[0160] The present application also provides a computer readable storage medium, the computer readable storage medium stores computer execution instructions, when the processor executes the computer execution instructions, the method for steering braking in emergency working condition is realized.

[0161] The above computer readable storage medium, the readable storage medium can be realized by any type of volatile or non-volatile storage device or their combination, 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.

[0162] An example readable storage medium is coupled to the processor such that the processor can read information from the readable storage medium and can write information to the readable storage medium. Of course, the readable storage medium can also be a part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0163] The division of the units is only a logical function division, and in actual implementation, another division manner can be used, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0164] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, can be located in one place or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0165] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0166] If the functions are realized in the form of software function units and sold or used as independent products, the functions can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0167] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The foregoing program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the foregoing storage medium includes various media capable of storing program codes, such as ROM, RAM, magnetic disk, or optical disk.

[0168] Finally, it should be noted that other embodiments of the present application will readily occur to those skilled in the art upon consideration of the specification and practice of the present application disclosed herein. The present application is intended to include all such variations as fall within the general scope of the application, and includes the generic principles disclosed and the best mode known to the inventors to be currently practiced as well as variations thereof, without departing from the scope of the present application as defined by the claims. The specification and examples give the best application of the present application as known to at least one of the inventors at the time of the filing of this application. It is to be understood that since numerous modifications and changes will readily occur to those skilled in the art, the application is not to be limited to the exact construction and operation as illustrated and described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims. The application is to be limited only by the claims.

Claims

1. A method of steering brake in emergency condition, characterized in that, The method comprises: obtaining a road curvature of a current road and a driving state of a 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 a desired longitudinal acceleration and a desired lateral acceleration according to the axle load transfer rate of the vehicle and the driving state; adjusting an opening degree 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.

2. The method of claim 1, wherein, The method of obtaining the desired longitudinal acceleration and the desired lateral acceleration according to the axle load transfer rate of the vehicle and the driving state comprises: if the axle load transfer rate is less than a safety threshold, obtaining the desired lateral acceleration according to a wheel angle and a vehicle speed correction value in the driving state, and obtaining the desired longitudinal acceleration according to a road adhesion force; if the axle load transfer rate is greater than or equal to the safety threshold, obtaining the desired lateral acceleration according to a lateral acceleration in the driving state, the safety threshold and the axle load transfer rate, and obtaining the desired longitudinal acceleration according to the desired lateral acceleration and a ground friction coefficient.

3. The method of claim 1, wherein, The method of obtaining the axle load transfer rate according to the driving state comprises: obtaining the axle load transfer rate according to vertical loads of four wheels of the vehicle in the driving state.

4. The method of claim 2, wherein, The method of obtaining the desired lateral acceleration according to the wheel angle and the vehicle speed correction value in the driving state, and obtaining the desired longitudinal acceleration according to the road adhesion force comprises: obtaining a desired lateral force according to the wheel angle and the vehicle speed correction value; obtaining the desired lateral acceleration according to the desired lateral force and a mass of the vehicle; obtaining a desired longitudinal force according to the desired lateral force and a friction force of the vehicle, and obtaining the desired longitudinal acceleration according to the desired longitudinal force and the mass of the vehicle.

5. The method of claim 4, wherein, Before the method of obtaining the desired lateral force according to the wheel angle and the vehicle speed correction value, the method further comprises: if a longitudinal vehicle speed in the driving state is less than or equal to a safety vehicle speed, obtaining the vehicle speed correction value according to the safety vehicle speed; if the longitudinal vehicle speed in the driving state is greater than the safety vehicle speed, taking the longitudinal vehicle speed in the driving state as the vehicle speed correction value.

6. The method of claim 4, wherein, The method of obtaining the desired lateral force according to the wheel angle and the vehicle speed correction value comprises: obtaining a first parameter according to a friction coefficient, a gravitational acceleration and the mass of the vehicle; obtaining a second parameter according to the wheel angle, the vehicle speed correction value and the mass of the vehicle; obtaining the desired lateral force according to a ratio of the first parameter and the second parameter.

7. The method of claim 2, wherein, The method of obtaining the desired lateral acceleration according to a lateral acceleration in the driving state, the safety threshold and the axle load transfer rate comprises: obtaining a ratio of the safety threshold and the axle load transfer rate, and obtaining the desired lateral acceleration according to the ratio and the lateral acceleration; Correspondingly, the method of obtaining the desired longitudinal acceleration according to the desired lateral acceleration and a ground friction coefficient comprises: obtaining a friction acceleration according to the ground friction coefficient and the gravitational acceleration; An expected longitudinal acceleration is obtained according to the friction acceleration and the expected lateral acceleration.

8. A steering brake device in an emergency working condition, characterized by comprising: The method comprises the steps of: a first obtaining module is configured to obtain a road curvature of a current road and a driving state of a vehicle on the current road; a judging module is 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 obtaining module 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; a processing module is configured to adjust an opening degree of a brake pedal of the vehicle according to the expected longitudinal acceleration and adjust a wheel rotation angle of the vehicle according to the expected lateral acceleration.

9. A steering brake apparatus in an emergency operation, characterized by comprising: The method comprises the steps of: 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 method for steering and braking in an emergency working condition according to any one of claims 1-7.

10. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method for steering and braking in an emergency working condition according to any one of claims 1-7.

Images