Background
In the field of intelligent networking automobiles, the integration of automobile, road and intelligent city networking is the current development trend across industries, and the technical development and maturity of an intelligent "+" networking "+" big data "cloud platform are the technical foundation and guarantee for realizing intelligent automobiles +".
The intelligent driving technology is one of the core technical fields of intelligent network-connected automobiles. Wherein, the environmental awareness and control decision is the core technical bottleneck of the intelligent driving system. At present, in the technical field of intelligent driving, the system environment perception capability is far immature, is a bottleneck in a technical bottleneck, and is also a key constraint factor for realizing intelligent driving. The bicycle sensing (vehicle-mounted sensor) and the bicycle-road cooperation (V2X) have limitations, and the combination of the bicycle sensing (vehicle-mounted sensor) and the bicycle-road cooperation (V2X) can realize breakthrough and leap of the intelligent sensing technology, so that the intelligent driving system is the most feasible system solution, the technical route and the direction at present. That is, the environment sensing capability of intelligent driving energy of the automobile is realized, and the sensing capability of the automobile is greatly enhanced by the fusion of the vehicle-mounted sensor and the vehicle-road cooperative information technology, so that the intelligent driving function, performance and safety and reliability of the automobile are greatly enhanced. Meanwhile, after the vehicle-road cooperative application is popularized, the intelligent perception cost of the bicycle can be greatly reduced.
The intelligent network-connected automobile based on the automobile-road cooperation is developed, the intelligent driving technology is realized, and the problem that the scene is super complex and changeable is solved, so that the intelligent network-connected automobile is a long road and a long process. Although the realization of full-automatic driving is a development direction of intelligent network-connected automobile technology, the realization of the full-automatic driving is a long-term goal, and a long path is required to be taken for realizing common commercial application. Market demand is a determinant of technological advances and landings. Recently, industry forms consensus, and the problems of traffic safety, traffic jam, traffic efficiency improvement and the like of key dangerous scenes are solved through a V2X technology, so that the method is the first most important market, and is also the problem of the biggest pain point of safe driving in traffic traveling, and the method is the problem to be gradually solved in decades later. That is, solving the driving safety problem of critical dangerous scenes is the most critical goal at present, and promotes the industrialization of technology to land.
ADAS is a typical system driver assistance system for solving driving safety, is also a technical basis for realizing automatic driving, is rapidly developing recently, and has a huge market. However, although ADAS system products have been applied to the market for many years, the technology is still far from mature, and the functions and performances of ADAS are severely limited by the perceptibility of the system. Especially in some special dangerous scenes, the ADAS can not realize an effective collision avoidance function. Through the V2X technology, the vehicle-mounted system and road side perception information realize fusion perception, so that the technical bottleneck of the system in the perception and decision algorithm in some high-risk scenes can be broken through, and an ADAS+ system with expanded functions and enhanced performance can be developed. The invention aims to solve the problem that the traditional ADAS system technology cannot solve one of high-risk scenes, namely a driving auxiliary control decision technology of an advanced driving auxiliary system (ADAS+) based on a V2X perception fusion technology under the condition that a front vehicle suddenly cuts into the scene.
Safe driving is the first rigidity requirement of the car user. In the driving process, the collision of the vehicle is a main factor causing traffic accidents, for example, when the vehicle is converged into a main road from a ramp, a driver is required to observe the road condition state of the main road in advance, pre-judgment is performed in advance, the vehicle is decelerated or stopped to avoid the main road, and once the driver fails to pay attention to the collision risk effectively, the collision of the vehicle can be caused to occur.
Although the prior art attempts to solve this problem, such as the conventional driving assistance systems of collision warning (FCW) and emergency braking Assistance (AEB), since the conventional driving assistance systems generally employ a sensor such as a camera or millimeter wave, the system can only find a target vehicle in a limited range due to the limitation of physical factors such as a detection angle and a detection range of the sensor and the existing target behavior prediction algorithm, and the risk prediction capability is greatly compromised.
In a word, the realization of intelligent driving has a lot of core technical bottlenecks, wherein the environment sensing technology and the vehicle control strategy are the core of the core and are also limiting factors of the intelligent driving system in the landing.
Disclosure of Invention
The invention aims to solve the technical problem of providing a driving assistance method, a vehicle, a computer and a storage medium based on a V2X perception fusion technology for reducing ramp incorporation risk.
In order to solve the technical problems, the first technical scheme adopted by the invention is as follows:
a driving assistance method based on a V2X perception fusion technology comprises the following steps
Step one, after a main vehicle enters a ramp road and a scene, judging whether a target vehicle exists on the rightmost side of the main road, if not, recording as an event A and normally driving, if yes, judging whether the main vehicle reaches a collision point first, if yes, judging whether TTC is larger than a first preset value and THW is larger than a first set threshold value after the main vehicle enters the main road, if yes, recording as an event C and normally driving, and if not, executing a step two, if not, predicting whether TTC is larger than the first preset value and THW is larger than a second set threshold value after the main vehicle fails to reach the collision point first, recording as an event B and normally driving, and if not, executing a step two;
Judging whether the distance between the safety line and the main vehicle is smaller than a third set threshold value of emergency braking, if yes, performing emergency braking and executing the third step, if not, judging whether the distance between the safety line and the main vehicle is smaller than a fourth set threshold value of mild braking, if yes, performing mild braking and executing the third step, if not, judging whether the distance between the safety line and the main vehicle is smaller than a fifth set threshold value of early warning, if not, performing early warning and executing the third step if normal running;
Thirdly, when at least one of the event A, the event B and the event C is met, the system exits from the alarm or the brake, and if the main vehicle is stopped, a driver is reminded to drive into the main road in time;
The TTC is the time of collision between the host vehicle and the target vehicle, and if the host vehicle reaches a collision point first, the calculation formula of the TTC is as follows:
If the host vehicle fails to reach the collision point first, the calculation formula of the TTC is as follows:
THW is the headway, and the calculation formula is:
Wherein vSV is the running speed of the host vehicle, vT is the running speed of the target vehicle, aSV is the acceleration of the host vehicle, aT is the acceleration of the target vehicle, and dR is the distance between the host vehicle and the target vehicle after entering the host road.
Further, the calculation formula of the third set threshold Dstop is as follows:
wherein tRBR is the brake system response time.
Further, the calculation formula of the fourth set threshold dstop is as follows:
wherein tSVD is the driver reaction time.
Further, the determining whether the host vehicle reaches the collision point first further includes
Firstly, judging the time T1 when the target vehicle reaches the collision point, wherein the calculation formula is as follows
Wherein dT is the distance from the target vehicle to the collision point;
judging the time T2 when the main vehicle reaches the collision point, wherein the calculation formula is as follows
Wherein dS is the distance from the host vehicle to the collision point;
If T1 is greater than or equal to T2, the host vehicle reaches the collision point first, otherwise the target vehicle reaches the collision point first.
Further, the first set threshold is 4.4s.
Further, the second set threshold is 1.2s.
Further, if there are a plurality of target vehicles, each target vehicle makes a judgment.
In order to solve the technical problems, the second technical scheme adopted by the invention is as follows:
A vehicle includes a controller that performs the above-described driving assistance method based on the V2X awareness fusion technique.
In order to solve the technical problems, a third technical scheme adopted by the invention is as follows:
A computer comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the above-described driving assistance method based on V2X aware fusion technique when executing the computer program.
In order to solve the technical problems, a fourth technical scheme adopted by the invention is as follows:
a storage medium readable by a computer and storing a computer program which, when executed by a processor, implements a driving assistance method based on the V2X awareness fusion technique as described above.
The auxiliary method has the advantages that when vehicles are converged into the main road from the ramp, the main road condition state is observed in advance by the main vehicle body through the main vehicle body pre-judgment instead of the driver, so that the target vehicles on the main road can be decelerated or parked to avoid, and a warning can be sent out, and the traffic accident caused by the collision of the vehicles is avoided once the driver fails to pay attention to the main road.
Detailed Description
In order to describe the technical contents, the achieved objects and effects of the present invention in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.
Referring to fig. 1 to 3, a driving assistance method based on V2X sensing fusion technology includes
Step one, after a main vehicle enters a ramp road and a scene, judging whether a target vehicle exists on the rightmost side of the main road, if not, recording as an event A and normally driving, if yes, judging whether the main vehicle reaches a collision point first, if yes, judging whether TTC is larger than a first preset value and THW is larger than a first set threshold value after the main vehicle enters the main road, if yes, recording as an event C and normally driving, and if not, executing a step two, if not, predicting whether TTC is larger than the first preset value and THW is larger than a second set threshold value after the main vehicle fails to reach the collision point first, recording as an event B and normally driving, and if not, executing a step two;
Judging whether the distance between the safety line and the main vehicle is smaller than a third set threshold value of emergency braking, if yes, performing emergency braking and executing the third step, if not, judging whether the distance between the safety line and the main vehicle is smaller than a fourth set threshold value of mild braking, if yes, performing mild braking and executing the third step, if not, judging whether the distance between the safety line and the main vehicle is smaller than a fifth set threshold value of early warning, if not, performing early warning and executing the third step if normal running;
Thirdly, when at least one of the event A, the event B and the event C is met, the system exits from the alarm or the brake, and if the main vehicle is stopped, a driver is reminded to drive into the main road in time;
The TTC is the time of collision between the host vehicle and the target vehicle, and if the host vehicle reaches a collision point first, the calculation formula of the TTC is as follows:
If the host vehicle fails to reach the collision point first, the calculation formula of the TTC is as follows:
THW is the headway, and the calculation formula is:
Wherein vSV is the running speed of the host vehicle, vT is the running speed of the target vehicle, aSV is the acceleration of the host vehicle, aT is the acceleration of the target vehicle, and dR is the distance between the vehicle and the target vehicle after entering the host road.
From the above description, according to the auxiliary method of the application, when the vehicles are led into the main road from the ramp, the pre-judgment is performed in advance by the main vehicle instead of the driver to observe the road condition state of the main road in advance, so that the target vehicles on the main road can be decelerated or parked to avoid, and the warning can be sent out, thereby avoiding the traffic accident caused by the collision of the vehicles once the driver fails to concentrate on the effective pre-judgment collision risk.
Further, the calculation formula of the third set threshold Dstop is as follows:
wherein tRBR is the brake system response time.
Further, the calculation formula of the fourth set threshold dstop is as follows:
wherein tSVD is the driver reaction time.
Further, the determining whether the host vehicle reaches the collision point first further includes
Firstly, judging the time T1 when the target vehicle reaches the collision point, wherein the calculation formula is as follows
Wherein dT is the distance from the target vehicle to the collision point;
judging the time T2 when the main vehicle reaches the collision point, wherein the calculation formula is as follows
Wherein dS is the distance from the host vehicle to the collision point;
If T1 is greater than or equal to T2, the host vehicle reaches the collision point first, otherwise the target vehicle reaches the collision point first.
Further, the first set threshold is 4.4s.
Further, the second set threshold is 1.2s.
Further, if there are a plurality of target vehicles, each target vehicle makes a judgment.
A vehicle includes a controller that performs the above-described driving assistance method based on the V2X awareness fusion technique.
A computer comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing a driving assistance method based on the V2X aware fusion technique as described above when executing the computer program.
A storage medium readable by a computer and storing a computer program which, when executed by a processor, implements a driving assistance method based on the V2X awareness fusion technique as described above.
Example 1
A driving assistance method based on a V2X perception fusion technology,
Reference is made to fig. 1 using a scene;
A system diagram of the individual participating principals is shown with reference to fig. 2;
logic control diagram of the host vehicle referring to figure 3,
In order to facilitate explanation of situation assessment and decision judgment logic of a ramp merging scene, relevant parameters are defined as follows:
the running speed of the rightmost vehicle (hereinafter, collectively referred to as the target vehicle) in the main road is vT;
the intersection point of the running direction of the main vehicle SV and the running direction of the target vehicle is a collision point O;
The distance dT of the target vehicle to the collision point O;
The acceleration of the target vehicle is aT;
the running speed of the main vehicle is vSV;
The distance between the main vehicle and the safety line (the intersection line of the right lane line of the rightmost lane of the main road and the ramp) is dp;
The acceleration of the main vehicle is aSV;
Distance ds from the host vehicle to collision point O;
The host vehicle driver response time is tSVD and the host vehicle brake system response time is tRBR.
① And judging whether the Flag of the target vehicle exists in the rightmost lane of the main lane near the scene according to the fusion sensing result of the V2I information, the V2V information, the main vehicle camera information, the forward millimeter wave radar information and the lateral angle radar information. If no target vehicle exists, the host vehicle can be normally integrated into the host channel, otherwise, further risk logic judgment is carried out.
② If the target vehicle exists in the lane on the right side of the main road, further judging whether the main vehicle has collision risk in and after the merging according to the motion relationship and the position relationship of the target vehicle and the main vehicle. For this purpose, the time relationship between the arrival of the target vehicle and the arrival of the host vehicle at the collision point O is determined. The calculation formula of the time T1 from the target vehicle to the point O is as follows:
the calculation formula of the time T2 from the main vehicle to the point O is as follows:
If T1 is more than or equal to T2, the main vehicle reaches the collision point first, otherwise, the target vehicle reaches the collision point first. If the host vehicle reaches the collision point first, after the host vehicle enters the host channel, whether the target vehicle is used as a rear vehicle and has collision risk to the host vehicle depends on the relative motion relation and the relative position relation of the two, but the logic relation between the speed of the target vehicle and the speed of the host vehicle is unknown, so that the interference degree of the host vehicle to the target vehicle after entering the host channel is predicted by using TTC and THW (headway) in a combined way under the condition of not decelerating:
Wherein dR is the distance between the vehicle and the target vehicle after entering the main road, if the value is positive to indicate that the target vehicle is preceded by the host vehicle after reaching the point O, otherwise, the host vehicle is positioned after the target vehicle. The calculation formula is as follows:
dR＝dT-T2*vT(3.5)
when TTC is larger than a set threshold (defaulting to 4.4 s) and THW is larger than the set threshold (defaulting to 1.2 s), the TTC and the THW are considered to have no collision risk, and the host vehicle can be normally integrated into the main road, otherwise, the collision risk exists.
If T1< T2, it is indicated that the target vehicle reaches the collision point first. Considering the influences of sensor delay errors, measurement errors, calculation errors and the like, the situation that the target vehicle reaches the collision point first cannot completely ensure that the target vehicle and the collision point have no collision risk, so that the target vehicle has driven a certain distance when the main vehicle enters the main road must be ensured. Also, the level of collision risk for both is commonly characterized using the TTC, THW two parameters:
when TTC is larger than the set threshold (defaulting to 4.4 s) and THW is larger than the set threshold (defaulting to 1.2 s), the TTC and the THW are considered to have no collision risk, and the host vehicle can be normally integrated into the main road, otherwise, the collision risk exists.
③ When the main vehicle and the target vehicle have collision risks, the degree of the main vehicle deceleration is controlled according to the degree of the collision risks. The risk level state of the collision is judged according to the distance between the main vehicle and the safety line.
A) The system can firstly judge whether the main vehicle is in a very urgent state, if the collision cannot be avoided through human intervention, the system is required to be automatically intervened, and the collision is avoided or reduced through strong emergency braking. And setting a system emergency braking trigger threshold, and starting emergency braking at the first time when the distance dp between the main vehicle and the safety line is smaller than the emergency braking trigger threshold. The emergency braking threshold is given by:
b) And secondly, the system can judge whether the main vehicle is in a relatively urgent state or not, and the system can remind through slow braking at the moment so as to expect the driver to actively take over the vehicle. When the distance dp of the main vehicle from the safety line is less than the mild braking trigger threshold, mild braking is initiated. The calculation formula of the mild braking threshold is the same as that of emergency braking, and the difference is that the value of aSV is consistent with the zebra crossing scene.
C) At the end of this period, the system will determine if the vehicle is in a potentially risky state, where the system is dominated by audible and visual alerts. And when the distance dp between the main vehicle and the safety line is smaller than the early warning trigger threshold value, starting an early warning function. The calculation formula of the early warning threshold value is as follows:
④ The system exits the alarm or brake when at least one of a (target vehicle is not present), B (host vehicle is behind the collision point and has been at a safe distance from the target vehicle), C (host vehicle is in front of the collision point and has been at a safe distance from the target vehicle) event is met. If the main vehicle is in a braking state, reminding a driver to drive into the main lane in time through an instrument or sound.
In addition, when a plurality of target vehicles exist, each target vehicle needs to carry out safety judgment, each target safety risk needs to be considered simultaneously, and when at least one target has collision risk, judgment of the safety risk level needs to be carried out, and corresponding strategies, emergency braking, mild braking or acousto-optic reminding are executed.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent changes made by the specification and drawings of the present invention, or direct or indirect application in the relevant art, are included in the scope of the present invention.