Vehicle rear collision early warning methodTechnical Field
The invention belongs to the technical field of automobiles, and relates to a vehicle rear collision early warning method.
Background
With the improvement of living conditions of people, automobiles become the walk-substituting work for each family, but the accompanying traffic accidents are more and more frequent, wherein the rear collision accident of the automobiles is more common.
As is well known, rear-end collisions often occur due to too small following distance and too high speed, delayed reflection, concentrated energy, sudden braking of a front vehicle and the like of a driver, and particularly, the speed of a highway or other roads is high, so that once a vehicle has a rear-end collision, a series of rear-end collisions are caused, the chain reaction is strong, and the casualty probability is high. In addition, in urban roads, in addition to rear-end collisions, accidents in which pedestrians are caught in the vehicle bottom and lost due to backing up of a driver occur in the event that a two-wheeled vehicle rear-end collision causes death of a rider.
For the collision accident occurring at the rear of the vehicle, the existing Chinese patent document discloses a vehicle rear collision early warning method which comprises the steps of obtaining the motion information of a target object behind the vehicle and the motion information of the vehicle; calculating the pre-collision time of the rear target object and the vehicle according to the motion information of the rear target object and the motion information of the vehicle, namely judging whether a front target object exists in front of the vehicle or not when the pre-collision time is less than or equal to a first time threshold value and the vehicle is in a static state; braking the vehicle when a front target object exists in front of the vehicle and the distance from the front target object to the vehicle is smaller than a first distance difference threshold value. Although the invention can avoid the secondary collision or the chain collision of the vehicle and reduce the collision loss, the invention only adopts the braking strategy to avoid the secondary collision, if the speed is higher during the collision, the invention still causes great damage to the personnel inside the vehicle and the personnel outside the vehicle, and the safety is lower.
Disclosure of Invention
The invention aims to provide a vehicle rear collision early warning method aiming at the problems in the prior art, and the technical problems to be solved are as follows: how to reduce the damage caused by the rear collision of the vehicle.
The purpose of the invention can be realized by the following technical scheme: a vehicle rear collision early warning method comprises the following steps:
A. acquiring a speed difference V1 and a distance difference S1 between the vehicle and a rear target object;
B. determining whether a front target object exists in front of the vehicle when the speed difference V1 is determined to be smaller than a first speed difference threshold value and the distance difference S1 is determined to be smaller than a first distance difference threshold value;
C. acquiring a speed difference V2 and a distance difference S2 between the front target object and the vehicle when the front target object exists; controlling the vehicle to perform an operation of accelerating forward when there is no forward target object;
D. controlling the vehicle to perform an operation of accelerating forward when it is determined that the speed difference V2 is greater than or equal to the second speed difference threshold and the distance difference S2 is greater than or equal to the second distance difference threshold; and controlling the vehicle to perform a braking operation or perform a lane change operation to an adjacent lane when the speed difference V2 is judged to be less than the second speed difference threshold and/or the distance difference S2 is judged to be less than the second distance difference threshold.
The working principle of the vehicle rear collision early warning method is as follows: the method comprises the steps that in the running process of a vehicle, the speed difference V1 and the distance difference S1 between the vehicle and a rear target object are obtained in real time, whether the vehicle has a front target object is judged when the speed difference V1 is smaller than a first speed difference threshold value and the distance difference S1 is smaller than a first distance difference threshold value, if the front target object does not exist or exists but the speed difference V2 between the front target object and the vehicle is larger than a second speed difference threshold value and the distance difference S2 is larger than a second distance difference threshold value, the vehicle is indicated to have an acceleration space, the vehicle is controlled to accelerate to avoid collision with the rear target object, and the running safety of the vehicle is guaranteed; when the speed difference V2 is smaller than the second speed difference threshold and/or the distance difference is smaller than the second distance difference threshold, there is a possibility that a rear collision of the own vehicle may cause a collision with a preceding vehicle target object, and at this time, a vehicle braking operation or a lane change operation is performed. Through the operation of braking, when the collision between the vehicle and the rear target object is unavoidable and the front target object is also in front, the condition that the vehicle still continues to move forwards to cause the collision with the front target object when the rear collision occurs can be avoided, the continuous traffic accidents are avoided, and the damage caused by the rear collision of the vehicle can be effectively reduced.
In the vehicle rear collision warning method, after the operation of accelerating and advancing is performed in the steps C and D, the acceleration a1 of the vehicle is acquired, whether the acceleration a1 is greater than the acceleration threshold is judged, and if the judgment result is yes, the seat belt pre-tightening function is started; and when the judgment result is negative, not performing the operation. The safety belt pre-tightening function is started, so that a driver and passengers in the vehicle can be safely fixed on the seat, the safe driving of the driver can be ensured, and the safety of the passengers in the vehicle can be ensured.
In the vehicle rear collision early warning method, before starting the safety belt pre-tightening function, the vehicle running speed before the vehicle accelerates and advances is also obtained, and when the vehicle running speed is smaller than the middle-gear speed threshold value, the safety belt pre-tightening function is not started; and when the running speed of the vehicle is greater than or equal to the middle-gear speed threshold value, starting a seat belt pre-tightening function. The judgment of the running speed of the vehicle is increased, and the execution accuracy of the seat belt pre-tightening function can be improved.
In the above-mentioned vehicle rear collision warning method, in the step D, the vehicle condition information of the adjacent lane is acquired when it is determined that the speed difference V2 is smaller than the second speed difference threshold or the distance difference S2 is smaller than the second distance difference threshold, it is determined whether an operation to change the lane to the adjacent lane is satisfied or not based on the vehicle condition information, and if so, the operation to change the lane to the adjacent lane is performed, and if not, the braking operation is performed. By adopting the way of changing the lane of the vehicle, the probability of collision with a rear target object can be effectively reduced, and the safety of the vehicle is improved.
In the vehicle rear collision warning method, the acquired vehicle state information of the adjacent lanes includes:
and acquiring the azimuth information and the running speed information of the vehicles on the adjacent lanes by the laser radar. By means of the direction information and the running speed information, whether the vehicle collides with the vehicle on the adjacent lane when changing lanes can be judged, and therefore safety of executing vehicle lane changing operation is improved.
In the above-described vehicle rear collision warning method, in the step D, the vehicle brake deceleration b1 is acquired when the vehicle is controlled to perform a braking operation, and the airbag ignition is activated when it is determined that the brake deceleration b1 is greater than the deceleration difference threshold.
In the above-described vehicle rear collision warning method, in the step D, the vehicle steering angular velocity w1 is acquired when the vehicle is controlled to perform an operation to change lanes to an adjacent lane, and the airbag ignition is activated when it is determined that the steering angular velocity w1 is greater than the angular velocity threshold.
When the braking deceleration b1 of the vehicle is greater than the deceleration threshold value or the steering angular velocity w1 is greater than the angular velocity threshold value, the airbag is started to explode, so that the driver and the passenger can be prevented from colliding with the hard point of the interior trim of the vehicle, the protection effect is achieved, and the injury to the personnel in the vehicle is reduced.
In the vehicle rear collision early warning method, the vehicle running speed before the vehicle lane change operation or the brake operation is acquired before the airbag detonation operation is started, and the airbag detonation is not started when the vehicle running speed is less than or equal to the low-gear speed threshold; and when the running speed of the vehicle is greater than the withstanding speed threshold value, starting the safety airbag to explode.
In the vehicle rear collision warning method, in the step B, a third speed difference threshold value is further set, where the third speed difference threshold value is smaller than the first speed difference threshold value, and when it is determined that the speed difference V1 is smaller than the first speed difference threshold value but greater than or equal to the third speed difference threshold value, a warning prompt is given to a rear target object; when the speed difference V1 is smaller than the third speed difference threshold value, it is determined whether a front target object exists in front of the vehicle. The third speed difference threshold value and the first speed difference threshold value are set, when the vehicle has collision risks, a prompt can be sent out, the risk that the vehicle has rear collision is reduced, and meanwhile the accuracy of the vehicle for executing rear collision early warning can be improved.
In the above vehicle rear collision warning method, in step D, the type of the rear target object is also identified when the braking operation is performed, and the pedestrian protection airbag at the rear of the vehicle is activated when the rear target object is not a motor vehicle; the pedestrian protection airbag is not activated when the rear object is an automobile.
Compared with the prior art, the vehicle rear collision early warning method has the following advantages:
1. the invention sends out early warning to the rear part of the vehicle by judging the speed difference and the distance difference between the front and rear target objects and the vehicle, adopts the early warning measures of acceleration, braking or lane change, reduces the accident probability of secondary collision or chain collision, and reduces the damage generated by the rear part of the vehicle.
2. The early warning measures of the invention also comprise the starting of the safety air bag, which solves the problem that the neck or the chest of the front passenger and the back passenger of the vehicle is injured due to the change of the vehicle speed after the early warning is generated, and effectively protects the safety of all the passengers and the driver in the vehicle.
3. The invention can also effectively protect the safety of pedestrians and two-wheel vehicle riders by igniting the pedestrian safety air bag at the rear part of the vehicle or reminding the pedestrians when identifying the rear target object position pedestrians and the two-wheel vehicle riders.
Drawings
Fig. 1 is a control flow chart of the present invention.
Fig. 2 is a control flow chart according to a first embodiment of the present invention.
Fig. 3 is a control flow chart of the second embodiment of the present invention.
Fig. 4 is a control flowchart of a third embodiment of the present invention.
Detailed Description
The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.
The first embodiment is as follows:
as shown in fig. 1 and 2, in the vehicle rear collision early warning method, in the vehicle driving process, whether a rear target object exists behind the vehicle is judged in real time, when the rear target object exists, a distance difference S1 and a speed difference V1 between the vehicle and the rear target object are obtained in real time, when the distance difference S1 is smaller than a first distance threshold and the speed difference V1 is smaller than a first speed threshold, at this time, whether the speed difference V1 is greater than or equal to a third speed threshold is further judged, and when the speed difference V1 is greater than or equal to the third speed threshold, the vehicle starts an early warning reminding function, and sends an image signal prompt, such as please keep words like a vehicle distance, or sends a sound signal prompt, and reminds the rear vehicle to pay attention to the vehicle distance;
the method comprises the steps of judging whether a front target object exists in front of a vehicle when the distance difference S1 is smaller than a first distance threshold value and the speed difference V1 is smaller than a third speed threshold value, controlling the vehicle to perform an acceleration advancing operation when the front target object does not exist, acquiring the acceleration a1 of the vehicle in real time after the vehicle is accelerated and acquiring the vehicle running speed before the vehicle is accelerated and advanced, starting a safety belt early warning function when the vehicle running speed is larger than a middle speed threshold value and the acceleration a1 is larger than the acceleration threshold value, and not performing the operation when the acceleration a1 is smaller than or equal to the acceleration threshold value or the vehicle running speed is smaller than or equal to the middle speed threshold value. Wherein the mid-range speed threshold may be set between 45-55km/h, preferably 50 km/h.
The distance difference S2 and the speed difference V2 between the front target object and the host vehicle are acquired when the front target object exists, and the vehicle is controlled to perform an acceleration forward operation when the distance difference S2 is determined to be greater than or equal to a second distance threshold and the speed difference V2 is determined to be greater than or equal to a second speed threshold. After the vehicle acceleration forward is executed, acquiring the acceleration a1 of the vehicle in real time, acquiring the running speed of the vehicle before the vehicle acceleration forward, starting a safety belt early warning function when the running speed of the vehicle is greater than a middle speed threshold value and the acceleration a1 is greater than an acceleration threshold value, and not operating when the acceleration a1 is less than or equal to the acceleration threshold value or the running speed of the vehicle is less than or equal to the middle speed threshold value.
Judging vehicle state information of an adjacent lane when the distance difference S2 is smaller than a second distance threshold value but the speed difference V2 is larger than or equal to the second speed threshold value, controlling the vehicle to perform lane changing operation when the speed and the distance of the vehicle of the adjacent lane meet lane changing requirements, acquiring steering angular speed w1 of the vehicle and the vehicle running speed before the vehicle turns, determining whether to start airbag detonation or not by judging the steering angular speed w1 and the vehicle running speed, and controlling the vehicle to perform operation of starting airbag detonation when the vehicle running speed is larger than a low-gear speed threshold value and the steering angular speed w1 is larger than the angular speed threshold value, wherein the low-gear speed threshold value can be set to be 15 km/h; not operating when the steering angular speed w1 is less than or equal to the angular speed threshold or the vehicle running speed is less than or equal to the low range speed threshold;
when the speed and the distance of the vehicle on the adjacent lane do not meet the lane change requirement, controlling the vehicle to perform a braking operation, acquiring the braking deceleration b1 of the vehicle, and when the braking deceleration b1 is greater than a deceleration threshold, starting the airbag to explode, so as to avoid the collision of a driver and a biogenesis with a hard point of an inner decoration of a passenger compartment, and playing a role of safety protection, wherein in order to ensure the accuracy of the airbag explosion, before the airbag explosion operation is performed, the vehicle running speed before the vehicle performs the braking operation is judged to be acquired, and when the vehicle running speed is less than a low-gear speed threshold, namely less than 15km/h, even if the braking deceleration b1 is greater than the deceleration threshold, the airbag is not started to explode; when brake deceleration b1 is less than or equal to the deceleration threshold, the airbag is not activated to explode, i.e., no operation is performed.
When the braking operation is executed, the type of the rear target object is identified, and whether the rear target object is a motor vehicle, namely whether the rear target object is a pedestrian or a two-wheel vehicle rider is judged. The condition of whether the rear target object is identified can also be added with the judgment of the vehicle running speed, and when the vehicle running speed is greater than the low-gear speed threshold value but less than the middle-gear speed threshold value, the type of the rear target object is identified. When the rear target object is identified as a pedestrian or a two-wheel vehicle rider, the pedestrian safety airbag at the rear part of the vehicle is started in addition to the braking operation, the safety of the head, the legs and other parts of the two-wheel vehicle rider is protected through the pedestrian safety airbag, and casualties are reduced; when the rear target object is identified as the motor vehicle, the pedestrian airbag is not started, namely, the operation is not executed.
In the embodiment, whether a front target object exists in front of the vehicle is judged through a front laser radar, the front laser radar transmits electromagnetic waves to the front of the vehicle, when a reflected signal exists, the front of the vehicle can be judged to exist the front target object, and the speed difference V2 and the distance difference S2 between the front target object and the vehicle of the vehicle and the speed difference and the distance difference between the front target object and the vehicle on an adjacent lane can be obtained through the front laser radar so as to judge whether accident damage can be reduced through lane change; the shape of a rear target object, the speed difference V1 and the distance difference S1 between the rear camera and the vehicle can be identified, and vehicle information on adjacent lanes can also be identified, so that whether accident damage can be reduced by lane changing is judged; the braking operation of the vehicle is realized through a braking system; the acceleration advancing operation of the vehicle is realized through an accelerator system; the steering operation of the vehicle is realized through a steering system; the safety belt pre-tightening operation on personnel in the vehicle is realized through the pre-tightened safety belt; detecting an acceleration a1 or a brake deceleration b1 of the own vehicle by an acceleration sensor; detecting a steering angular velocity w1 of the host vehicle by an angular velocity sensor; the ACU controller is used for processing the information acquired by the front laser radar and the information acquired by the rear camera and sending various control instructions, such as controlling the vehicle to advance in an accelerating way, controlling the vehicle to change the lane, controlling the vehicle to brake, pre-tightening the safety belt, igniting the safety air bag in the vehicle and the safety air bag for pedestrians outside the vehicle, and the like. The ACU controller is an auxiliary controller for safety control in the vehicle, and can also be integrated in a vehicle controller of the vehicle.
Various thresholds appearing in the vehicle rear collision early warning method are pre-stored in the ACU controller, wherein the various thresholds can be set manually and are not fixed, and related personnel can set the thresholds according to the driving condition, so that the accuracy and the safety of the vehicle rear collision early warning are improved. In the present embodiment, the setting of the threshold is exemplified, and the first speed difference threshold may be set between 3-6km/h, preferably, may be set to 5 km/h; the second speed vehicle threshold value and the first speed difference threshold value are set to be the same, and the third speed difference threshold value can be set between-2 km/h and 0km/h, and preferably can be set to be 0 km/h; the first distance difference threshold and the second distance difference threshold may be set between 3 and 6m, and preferably, may be set to 5 m.
Example II,
As shown in fig. 1 and 3, the technical solution in this embodiment is substantially the same as the technical solution in the first embodiment, except that the vehicle state information of the adjacent lane is determined when the distance difference S1 is determined to be less than the first distance threshold and the speed difference V1 is determined to be less than the third speed threshold, and when the distance difference S2 is determined to be greater than or equal to the second distance threshold and the speed difference V2 is determined to be less than the second speed threshold, the vehicle is controlled to perform the lane change operation when the speed and distance of the vehicle in the adjacent lane satisfy the lane change requirement, the steering angular speed w1 of the vehicle is also obtained and the vehicle running speed before the vehicle turns is also obtained, whether to initiate the airbag spot explosion is determined by determining the steering angular speed w1 and the vehicle running speed, the vehicle is controlled to perform the airbag spot explosion initiating operation when the vehicle running speed is greater than the low range speed threshold and when the steering angular speed w1 is greater than the angular speed threshold, wherein the low gear speed threshold value can be set to 15 km/h; not operating when the steering angular speed w1 is less than or equal to the angular speed threshold or the vehicle running speed is less than or equal to the low range speed threshold;
when the speed and the distance of the vehicle on the adjacent lane do not meet the lane change requirement, controlling the vehicle to perform a braking operation, acquiring the braking deceleration b1 of the vehicle, and when the braking deceleration b1 is greater than a deceleration threshold, starting the airbag to explode, so as to avoid the collision of a driver and a biogenesis with a hard point of an inner decoration of a passenger compartment, and playing a role of safety protection, wherein in order to ensure the accuracy of the airbag explosion, before the airbag explosion operation is performed, the vehicle running speed before the vehicle performs the braking operation is judged to be acquired, and when the vehicle running speed is less than a low-gear speed threshold, namely less than 15km/h, even if the braking deceleration b1 is greater than the deceleration threshold, the airbag is not started to explode; when brake deceleration b1 is less than or equal to the deceleration threshold, the airbag is not activated to explode, i.e., no operation is performed.
Example III,
As shown in fig. 1 and 4, the technical solution in this embodiment is substantially the same as that in the first embodiment, except that when it is determined that the distance difference S1 is smaller than the first distance threshold and the speed difference V1 is smaller than the third speed threshold, and when the distance difference S2 is smaller than the second distance threshold and the speed difference V2 is smaller than the second speed threshold, the vehicle is controlled to perform a braking operation, at which the vehicle running speed before the vehicle performs the braking operation and the braking deceleration b1 of the vehicle are acquired; at this time, it is also determined whether the vehicle running speed before the brake operation is within the range of the low-range speed threshold value and the mid-range speed threshold value, and when the vehicle running speed is greater than the low-range speed threshold value but less than the mid-range speed threshold value, the type of the rear target object is identified, and it is determined whether the rear target object is a motor vehicle, that is, a pedestrian or a two-wheel vehicle rider.
When the braking deceleration b1 is greater than the deceleration threshold and the vehicle running speed is greater than the low-gear speed threshold, the safety airbag is started to explode, so that the situation that a driver and a biogenesis impact hard points in a passenger compartment is avoided, and the safety protection effect is achieved; when the rear target object is identified as the motor vehicle, the pedestrian safety airbag is not started, namely, the operation is not executed; in addition, the method can also play a role in safety protection when the vehicle is in a standing state or in a backing mode, for example, when the pedestrian or a two-wheel vehicle rider and the vehicle meet the conditions, the early warning reminding function is started or a pedestrian safety airbag is started for protection.
Example four:
the technical solution in this embodiment is substantially the same as that in the first and second embodiments, except that when it is determined that the distance difference S2 is less than the second distance threshold but the speed difference V2 is greater than or equal to the second speed threshold, or when it is determined that the distance difference S2 is greater than or equal to the second distance threshold but the speed difference V2 is less than the second speed threshold, and when the speed and distance of the vehicle in the adjacent lane do not satisfy the lane change requirement, an acceleration value of the vehicle is acquired based on the distance difference S1, the distance difference S2, the speed difference V1, and the speed difference V2 before the braking operation is performed, and the vehicle is accelerated and advanced until a condition that the speed difference V2 is less than the second speed difference threshold and the distance difference S2 is less than the second distance difference threshold is satisfied, and the vehicle is controlled to perform the braking operation to avoid the occurrence of the rear collision as much as possible.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.