V2V-based emergency braking control method for a host vehicle in a situation where a preceding vehicle is blocked

Abstract

This invention discloses a vehicle emergency braking control method based on V2V when the preceding vehicle is obstructed. An onboard unit is installed on each vehicle, enabling them to share their respective driving information with other vehicles. Each vehicle makes a braking judgment based on the shared driving information from the preceding vehicle and brakes accordingly. Using this invention, when the preceding vehicle is decelerating or braking suddenly and the preceding vehicle fails to respond in time, the system can promptly make judgments and perform warnings, deceleration, and emergency braking, thus avoiding collisions or reducing the severity of collision damage.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of intelligent auxiliary driving of vehicles, in particular to a self-vehicle emergency braking control method under the condition that the front-front vehicle is blocked based on V2V. BACKGROUND

[0002] During the driving of vehicles on the road, the driver can only see the front vehicle and can only make speed-up, speed-down, braking and other operation decisions according to the speed of the front vehicle, the distance from the front vehicle and other information. When the front-front vehicle is blocked by the current vehicle and the front-front vehicle suddenly slows down or brakes in an emergency, if the front vehicle fails to respond in time, the self-vehicle is likely to collide with the front vehicle and the front-front vehicle, endangering the life safety of the driver and passengers. SUMMARY

[0003] Therefore, the present application provides a self-vehicle emergency braking control method under the condition that the front-front vehicle is blocked based on V2V, which can make timely decisions and give warnings, slow down, brake in an emergency and other operations when the blocked front-front vehicle slows down or brakes in an emergency and the front vehicle fails to respond in time, so as to avoid collisions or reduce the damage degree of collisions.

[0004] In order to solve the above technical problems, the present application is implemented as follows:

[0005] The self-vehicle emergency braking control method under the condition that the front-front vehicle is blocked based on V2V installs an on-board unit (OBU) on each vehicle, so that the vehicles share their respective driving information with other vehicles; the vehicles make braking decisions according to the driving information shared by the front-front vehicle, and brake according to the results of the braking decisions.

[0006] Preferably, braking decisions are made for the front vehicle or the front-front vehicle respectively and independently; according to the command priority relationship, the command with the highest priority is executed among the two braking decisions for the front vehicle or the front-front vehicle.

[0007] Preferably, the braking decisions include:

[0008] Step 1: obtaining the driving information of the target vehicle through the OBU, the vehicle-mounted camera and / or the millimeter wave radar;

[0009] Step 2: obtaining the general collision time T and the minimum collision time T hw from the driving information;

[0010] Step 3: comparing the general collision time T with a set of general judgment thresholds, and outputting a general braking command according to the comparison result;

[0011] Step 4: comparing the minimum collision time T hw with a set of minimum judgment thresholds, and outputting a minimum braking command according to the comparison result;

[0012] Step 5, according to the outputs of the step 3 and the step 4, executing the command with the highest priority between the general braking command and the minimum braking command according to the command priority relationship.

[0013] Preferably, the driving information is the speed, acceleration and / or position of the vehicle.

[0014] Preferably, the general collision time T is divided into a first general collision time T ts and a second general collision time T tc .

[0015] The first general collision time T ts is when the acceleration of the host vehicle and the target vehicle is not equal and the condition (v TV -v SV ) 2 -2×(a TV -a SV )×x c >0 is met,

[0016]

[0017] wherein a TV is the acceleration of the target vehicle, a SV is the acceleration of the host vehicle, v SV is the speed of the host vehicle, V TV is the speed of the target vehicle, and x c is the distance between the host vehicle and the target vehicle.

[0018] The second general collision time T tc is when the acceleration of the host vehicle and the target vehicle is equal, or the condition (v TV -v SV ) 2 -2×(a TV -a SV )×x c >0 is not met, wherein v r is the relative speed between the host vehicle and the target vehicle.

[0019] Preferably, the minimum collision time T hw is,

[0020] Preferably, the general judgment threshold includes a general emergency braking time threshold T1, a general gentle stop time threshold T2, and a general warning time threshold T3; the general judgment threshold is calibrated according to actual conditions; when T

[0021] Preferably, the minimum judgment threshold includes a minimum emergency braking time threshold T4, a minimum gentle stop time threshold T5, and a minimum warning time threshold T6; the minimum judgment threshold is calibrated according to actual conditions; when T hw <T4, an emergency braking command is output; when T4 hw <T5, a gentle stop command is output; when T5 hw <T6, a warning command is output; otherwise, a normal driving command is output.

[0022] Preferably, the command priority relationship is emergency braking > gentle stop > warning > normal driving.

[0023] Preferably, steps 3 and 4 are performed synchronously.

[0024] Beneficial effects:

[0025] 1. The present application can make timely deceleration, emergency braking and other operations through analyzing the information output by the vehicle-mounted camera, millimeter wave radar and surrounding vehicle-mounted unit, so as to effectively avoid collision or reduce the damage degree of collision.

[0026] 2. The present application can further improve safety by installing OBU on the vehicle for V2V communication, and still making braking judgment when the preceding vehicle is shielded and does not respond in time.

[0027] 3. The present application can effectively avoid accidents or reduce the harm degree of accidents in the scene of high-speed road with many vehicles and fast driving speed through automatic processing of the algorithm.

[0028] 4. The present application further improves safety guarantee by setting the minimum collision time on the basis of judgment according to relative speed and acceleration.

[0029] 5. The present application can not only distinguish the output scene of different commands, but also can be flexibly adjusted according to different use scenes by calibrating the judgment threshold according to actual conditions, thereby improving the applicability of the method.

[0030] 6. The present application can guarantee driving comfort as much as possible on the basis of guaranteeing the basic purpose of driving safety by setting the command priority relationship. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating the decision-making process for a straight-line driving scenario where the vehicle in front is obstructed, based on an embodiment of the present invention. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] This invention provides a V2V-based emergency braking control method for a vehicle when the preceding vehicle is obstructed. The core idea is as follows:

[0034] An onboard unit (OBU) is installed on each vehicle, enabling the vehicles to share their driving information with other vehicles; the vehicles make braking decisions based on the driving information and brake according to the results of the braking decisions.

[0035] As can be seen, by analyzing information emitted by the onboard units of surrounding vehicles, this invention enables the vehicle to promptly perform deceleration and emergency braking when the vehicle in front, which is obstructed, slows down or brakes suddenly without responding in time. This effectively avoids collisions or reduces the severity of collision damage. In high-speed traffic scenarios with heavy traffic, this control method can effectively prevent accidents or reduce their severity.

[0036] The present invention will be further described in detail below with reference to an embodiment.

[0037] Three vehicles are already traveling in the same lane. This vehicle is designated SV, the vehicle in front is designated TV2, and the vehicle before that is designated TV1. TV1 is completely obscured by TV2. By installing OBUs on each vehicle, they can communicate wirelessly with surrounding vehicles (V2V communication), sharing information such as speed, acceleration, and position. After receiving information from other vehicles, SV further determines whether each set of information belongs to TV1, TV2, or a vehicle in another location based on the position information contained within. SV can further acquire information such as the speed, acceleration, and distance of TV2 through its onboard camera and millimeter-wave radar. SV also receives information about the speed, acceleration, and position of TV1 from its OBU via its onboard OBU. This embodiment specifically includes the following four steps:

[0038] Step 1: Using TV2 and TV1 as target vehicles respectively, the SV vehicle is judged using the Time-To-Collision (TTC) model. The TTC model specifically includes the following two cases:

[0039] Case a: When the accelerations of the SV vehicle and the target vehicle are not equal, assume that both accelerations remain constant, and their vehicle speeds, accelerations, and inter-vehicle distances satisfy the condition (v TV - v SV ) 2 - 2×(a TV - a SV )×x c > 0. In this case, the first general collision time T ts is:

[0040]

[0041] where a TV is the acceleration of the target vehicle (m / s 2 ), a SV is the acceleration of the SV vehicle (m / s 2 ), v SV is the vehicle speed of the SV vehicle (m / s), v TV is the vehicle speed of the target vehicle (m / s), and x c is the inter-vehicle distance (m).

[0042] Case b: When the accelerations of the SV vehicle and the target vehicle are equal, or their vehicle speeds, accelerations, and inter-vehicle distances do not satisfy the condition (v TV - v SV ) 2 - 2×(a TV - a SV )×x c > 0. In this case, the second general collision time T tc is:

[0043]

[0044] where v r is the relative vehicle speed of the two vehicles (m / s).

[0045] Step 2: After obtaining the general collision time T (either T ts or T tc ) through Step 1, according to the set emergency braking time threshold T1, gentle braking stop time threshold T2, and warning time threshold T3, when the collision time T < T1, output an emergency braking command; when T < T2, output a gentle braking stop command; when T < T3, output a warning command; otherwise, do not intervene and the vehicle travels normally. Among them, T1, T2, and T3 need to be calibrated according to the actual situation.

[0046] Step 3: Calculate the minimum collision time T hw from the following formula based on the inter-vehicle distance and the vehicle speed of the SV vehicle:

[0047]

[0048] Calibrate the emergency braking time threshold T4, gentle braking stop time threshold T5, and warning time threshold T6 according to the actual situation. When the collision time T hw < T4, output an emergency braking command; when T hw < T5, output a gentle braking stop command; when T hw < T6, output a warning command; otherwise, do not intervene and the vehicle travels normally. The judgment thresholds calibrated according to the actual situation not only distinguish the output scenarios of different commands, but can also be flexibly adjusted according to different usage scenarios, improving the applicability of the method

[0049] Step 4, as Figure 1 shown, according to the priority relationship: emergency braking > gentle braking stop > warning > normal driving, execute the command with the highest priority among the commands output in Step 2 and Step 3. By setting the command priority relationship, while ensuring the basic purpose of driving safety, the ride comfort is also ensured as much as possible.

[0050] Among them, the longitudinal safety control strategy of the SV vehicle for the TV2 vehicle adopts the method of the above Steps 1 to 4, and the longitudinal safety control strategy of the SV vehicle for the TV1 vehicle also adopts the method of the above Steps 1 to 4. The judgment of the SV vehicle for the TV2 vehicle and the TV1 vehicle is completely independent, and finally the command with the highest priority among the two judgment results is executed.

[0051] In summary, the above is only a preferred embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for emergency braking control of a vehicle when its preceding vehicle is obstructed, based on V2V technology, characterized in that: An on-vehicle unit (OBU) is installed on each vehicle so that the vehicle shares its respective driving information with other vehicles; the vehicle makes a braking judgment based on the driving information shared by the vehicle in front of its front vehicle and brakes according to the result of the braking judgment. The braking judgment includes: Step 1, obtain the driving information of the target vehicle through the OBU, on-vehicle camera and / or millimeter-wave radar. Step 2: Obtain the general collision time T and the minimum collision time T based on the driving information. hw ; Step 3, compare the general collision time T with a set of general judgment thresholds and output a general braking command according to the comparison result. Step 4, the minimum collision time T hw Compare with a set of minimum judgment thresholds, and output the minimum braking command based on the comparison result; Step 5, according to the outputs of Step 3 and Step 4, execute the command with the highest priority among the general braking command and the minimum braking command according to the command priority relationship. The general collision time T is divided into a first general collision time T, depending on the situation. ts Second general collision time T tc ; First general collision time T ts For example, when the accelerations of the vehicle and the target vehicle are not equal and the condition (v) is met. TV -v SV ) 2 -2×(a TV -a SV )×x c When >0, Among them, a TV Let a be the acceleration of the target vehicle. SV v is the acceleration of this vehicle. SV v is the speed of this vehicle. TV x is the speed of the target vehicle. c This is the inter-vehicle distance between this vehicle and the target vehicle; The second general collision time T tc For example, when the acceleration of this vehicle is equal to that of the target vehicle, or when the condition (v) is not met. TV -v SV ) 2 -2×(a TV -a SV )×x c When >0, Among them, v r This represents the relative speed between our vehicle and the target vehicle.

2. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... Make braking judgments independently for the vehicle in front or the vehicle in front of the front vehicle respectively; for the results of the two braking judgments obtained for the vehicle in front or the vehicle in front of the front vehicle, execute the command with the highest priority according to the command priority relationship.

3. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... The driving information is: the speed, acceleration and / or position of the vehicle.

4. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... The minimum collision time 5. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... The general judgment thresholds include a general emergency braking time threshold T1, a general gentle stop time threshold T2, and a general warning time threshold T3; the general judgment thresholds are calibrated according to the actual situation. When T < T1, output an emergency braking command; when T1 < T < T2, output a gentle stop command; when T2 < T < T3, output a warning command. Otherwise, output a normal driving command.

6. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... The minimum judgment thresholds include a minimum emergency braking time threshold T4, a minimum gentle stop time threshold T5, and a minimum warning time threshold T6; the minimum judgment thresholds are calibrated according to the actual situation. When T hw <When T < T4, output an emergency braking command; when T4 < T hw <T5, output a gentle braking stop command; when T5 < T hw <T6, output a warning command; Otherwise, output a normal driving command.

7. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 2, is characterized in that... The command priority relationship is: emergency braking > gentle stop > warning > normal driving.

8. The emergency braking control method for a vehicle under V2V-based conditions where the preceding vehicle is obstructed, as described in claim 1, is characterized in that... Step 3 and Step 4 are carried out synchronously.

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