CN111640299A - Reverse overtaking early warning method and system in V2X vehicle networking environment - Google Patents

Abstract

The invention discloses a reverse overtaking early warning method and a reverse overtaking early warning system under a V2X vehicle networking environment, which relate to the field of intelligent driving, wherein the method comprises the steps of obtaining and analyzing a V2X communication message set to obtain motion states of HV, RV-1 and RV-2; establishing a lane change safe distance model, and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model; establishing an acceleration overtaking model, and calculating acceleration overtaking time and constant-speed overtaking time to obtain the minimum longitudinal safety distance between HV and RV-1 after overtaking is finished based on the established acceleration overtaking model; establishing a reverse overtaking safe distance model, and calculating to obtain a HV reverse overtaking longitudinal minimum safe distance based on the established reverse overtaking safe distance model; and judging whether reverse overtaking safety risks exist at present or not, and performing early warning. According to the invention, the integrated reverse overtaking model is established, so that the complex reverse overtaking risk can be accurately identified.

Description

Reverse overtaking early warning method and system in V2X vehicle networking environment

Technical Field

The invention relates to the field of intelligent driving, in particular to a reverse overtaking early warning method and system in a V2X vehicle networking environment.

Background

The reverse overtaking scene is one common scene among a plurality of vehicle-vehicle interaction scenes under a road environment, and through a V2X (vehicle-to-outside information exchange) vehicle networking technology, a vehicle can acquire vehicle motion state information possibly appearing in a reverse lane, which is an important means for solving the problem that the current single-vehicle intelligent driving remote target detection capability is insufficient, and can effectively avoid traffic accidents between opposite vehicles during reverse overtaking.

The reverse overtaking process consists of a lane changing process and an accelerated overtaking process, the two latter processes have mature safe distance models, however, the analysis of a multi-vehicle motion mechanism in the overtaking process is lacked, so that the reverse overtaking process cannot be completely suitable for a reverse overtaking scene with multi-vehicle interaction. In addition, the problem of inaccurate system delay and positioning accuracy exists in multi-vehicle information interaction based on the V2X vehicle networking technology, and the conventional safe distance model only considers the problem of vehicle motion state change and does not take delay and positioning factors into consideration.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a reverse overtaking early warning method and a reverse overtaking early warning system in a V2X vehicle networking environment, and the accurate identification of complex reverse overtaking risks can be realized by establishing an integrated reverse overtaking model.

In order to achieve the above purpose, the invention provides a reverse overtaking early warning method under a V2X vehicle networking environment, which comprises the following steps:

acquiring and analyzing a V2X communication message set to obtain motion states of HV, RV-1 and RV-2;

establishing a lane change safe distance model, and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model;

establishing an accelerated overtaking model according to the HV motion state after the first lane change is finished, and calculating accelerated overtaking time and constant-speed overtaking time based on the established accelerated overtaking model;

calculating to obtain the minimum longitudinal safe distance between the HV and the RV-1 after overtaking according to the HV motion state after overtaking and the established lane change safe distance model;

establishing a reverse overtaking safe distance model according to a multi-vehicle motion mechanism and a lane change safe distance model in the reverse overtaking process, and calculating to obtain an HV reverse overtaking longitudinal minimum safe distance based on the established reverse overtaking safe distance model;

and judging whether reverse overtaking safety risks exist at present or not according to the current multi-vehicle motion state, the minimum longitudinal safety distance and the HV reverse overtaking longitudinal minimum safety distance, and performing early warning.

On the basis of the technical scheme, the calculation of the minimum longitudinal safe distance during the first lane change comprises the following specific calculation steps:

calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Vehicle body representing RV-1Length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIndicating a threshold value of the time required for completing the first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1;

according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yDenotes the duration of the lateral shift of the HV, τ denotes the time of the lateral shift of the HV, h denotes the lateral shift distance of the HV at the completion of the first lane change, y_hv(t) represents the lateral displacement of HV during the lane change;

according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

wherein S is_flc(t) represents the relative distance between HV and RV-1 at time t during the lane change, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of the HV,a_rv1(τ) represents the instantaneous acceleration of RV-1, λ represents the integral variable;

relative distance S between two vehicles HV and RV-1 at initial lane change time for the first time_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount, S, of HV at the initial time_flc(t₀) The minimum value of (a) is the minimum longitudinal safety distance in the first lane change;

calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

On the basis of the technical scheme, the calculating of the acceleration overtaking time and the uniform speed overtaking time specifically comprises the following steps:

calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

And calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Represents the relative distance between HV and RV-1 after the first lane change is finished;

calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a constant speed overtaking time.

On the basis of the technical scheme, the minimum longitudinal safe distance between the HV and the RV-1 after the overtaking is finished is obtained through calculation, and the calculation process is as follows:

and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass；

According to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking.

On the basis of the technical proposal, the device comprises a shell,

the calculation is carried out to obtain the HV reverse overtaking longitudinal minimum safe distance, and the specific calculation steps comprise:

and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) represents the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of the target lane after the HV completes the first lane change;

after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

the reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV, RV1), there is a lane change collision risk, otherwise it is not present; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

The invention provides a reverse overtaking early warning system under a V2X vehicle networking environment, which comprises:

the multi-vehicle target state extraction module is used for acquiring and analyzing a V2X communication message set to obtain motion states of HV, RV-1 and RV-2;

the first lane change safe distance calculation module is used for establishing a lane change safe distance model and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model;

the acceleration overtaking calculation module is used for establishing an acceleration overtaking model according to the HV motion state after the first lane change is finished, and calculating acceleration overtaking time and constant-speed overtaking time based on the established acceleration overtaking model;

the second lane change safe distance calculation module is used for calculating and obtaining the minimum longitudinal safe distance between the HV and the RV-1 after the overtaking is finished according to the HV motion state after the overtaking is finished and the established lane change safe distance model;

the reverse overtaking safety distance calculation module is used for establishing a reverse overtaking safety distance model according to a multi-vehicle motion mechanism and a lane change safety distance model in the reverse overtaking process, and calculating to obtain an HV reverse overtaking longitudinal minimum safety distance based on the established reverse overtaking safety distance model;

and the reverse overtaking safety early warning module is used for judging whether reverse overtaking safety risks exist at present or not according to the current multi-vehicle motion state, the minimum longitudinal safety distance and the HV reverse overtaking longitudinal minimum safety distance and carrying out early warning.

On the basis of the technical scheme, the calculation of the minimum longitudinal safe distance during the first lane change includes the following specific calculation processes:

calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Denotes RV-1 body length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIs shown to be finishedThreshold value of time length required for first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1;

according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yDenotes the duration of the lateral shift of the HV, τ denotes the time of the lateral shift of the HV, h denotes the lateral shift distance of the HV at the completion of the first lane change, y_hv(t) represents the lateral displacement of HV during the lane change;

according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

wherein S is_flc(t) represents the relative distance between HV and RV-1 at time t during the lane change, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of HV, a_rv1(τ) represents the instantaneous acceleration of RV-1, λ represents the integral variable;

initial time of first channel change HV and RV-1 relative distance S between two vehicles_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount, S, of HV at the initial time_flc(t₀) The minimum value of (a) is the minimum longitudinal safety distance in the first lane change;

calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

On the basis of the technical scheme, the calculating of the accelerated overtaking time and the uniform overtaking time comprises the following specific calculating processes:

calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

And calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Represents the relative distance between HV and RV-1 after the first lane change is finished;

calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a uniform overtaking time, SD_slc(HV, RV1) represents the minimum longitudinal safety distance between HV and RV-1 after the completion of the overtaking.

On the basis of the technical scheme, the minimum longitudinal safe distance between the HV and the RV-1 after the overtaking is finished is obtained through calculation, and the calculation process is as follows:

and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass；

According to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking.

On the basis of the technical proposal, the device comprises a shell,

the calculation is carried out to obtain the HV reverse overtaking longitudinal minimum safe distance, and the specific calculation steps comprise:

and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) represents the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of the target lane after the HV completes the first lane change;

after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

the reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV, RV1), there is a lane change collision risk, otherwise it is not present; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

Compared with the prior art, the invention has the advantages that: based on V2V information interaction, basic safety attribute information of multiple vehicles in a reverse overtaking scene is obtained, necessary motion states and vehicle static attribute data are extracted, a lane change safety distance model is combined on the basis of considering system time delay and positioning accuracy, a complex reverse overtaking process is resolved into four processes of switching to a target lane, accelerating overtaking, uniform overtaking and switching to an original lane through analysis of a multi-vehicle motion mechanism, an integrated reverse overtaking model is built, and accurate identification of complex reverse overtaking risks is achieved.

Drawings

FIG. 1 is a flowchart of a reverse overtaking warning method in a V2X vehicle networking environment according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a reverse overtaking scenario according to an embodiment of the invention.

Detailed Description

The embodiment of the invention provides a reverse overtaking early warning method under a V2X car networking environment, which is characterized in that basic safety attribute information of multiple cars under a reverse overtaking scene is obtained based on V2V information interaction, an integrated reverse overtaking model is established by extracting necessary motion states and static attribute data of the cars and combining a lane change safety distance model on the basis of considering system time delay and positioning accuracy, and accurate identification of complex reverse overtaking risks is realized. The embodiment of the invention correspondingly provides a reverse overtaking early warning system in a V2X vehicle networking environment. The present invention will be described in further detail with reference to the accompanying drawings and examples. In the embodiment of the invention, HV, Host Vehicle, represents an overtaking Vehicle; RV, real Vehicle, wherein RV-1 represents the Vehicle to be overtaken in front of the overtaking Vehicle, and RV-2 represents the Vehicle traveling in the reverse lane.

Referring to fig. 1, the reverse overtaking early warning method in the V2X car networking environment provided by the embodiment of the present invention includes the following steps:

s1: and acquiring and analyzing the V2X communication message set to obtain the motion states of HV, RV-1 and RV-2.

In the embodiment of the invention, the reverse overtaking process comprises four processes of switching to a target lane, accelerating overtaking, overtaking at a constant speed and switching to an original lane, wherein the switching to the target lane refers to changing the lane from a current lane to the reverse lane, which is the first lane change; the target lane refers to a reverse lane; the accelerated overtaking and the uniform overtaking are both carried out in a target lane; switching to the original lane is from the target lane back to the original lane, which is a second lane change. Fig. 2 is a schematic diagram of a reverse overtaking scene according to an embodiment of the present invention.

S2: and establishing a lane change safe distance model, and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model.

In the embodiment of the invention, the minimum longitudinal safe distance during the first lane change is calculated, and the specific calculation steps comprise:

s201: calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Denotes RV-1 body length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIndicating a threshold value of the time required for completing the first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1. When the HV switches to the target lane, corner hits or lateral scratches are likely to occur with RV-1.

S202: according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yThe lateral displacement time period of the HV is represented,h represents the transverse displacement distance of HV when the first lane change is completed, y_hv(t) represents the lateral displacement of HV during a lane change, and τ represents the time for the lateral displacement of HV. If a lane change collision occurs when the HV is switched to the target lane, the time T required for the collision can be obtained_c,1＝y_hvAnd y is_hv∈ (0,0.5LW), LW denotes lane width.

S203: according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

wherein S is_flc(t) represents the relative distance between HV and RV-1 at time t during the lane change, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of HV, a_rv1(tau) represents the instantaneous acceleration of RV-1, lambda represents the integral variable, and the value range is [0, 1%]。

S204: the calculation formula of the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process is converted, so that the following can be obtained:

S_flc(t)＝x_rv1(t)-x_hv(t)-L_rv1-W_hvsin(θ(t))-D_err-d_td

t∈(t₀+T_lc,t₀+T_long)

s205: relative distance S between two vehicles HV and RV-1 at initial lane change time for the first time_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Indicating the amount of longitudinal displacement of the HV at the initial time. S_flc(t₀) Is the minimum longitudinal safety distance at the first lane change.

In the first lane changing process, if other vehicles run at a constant speed, in order to ensure safety, the HV decelerates in a very short time, then the lane is changed at a constant speed, and the acceleration is a_hv. At t₀+T_longAt the moment, the HV speed is equal to the RV-1 speed, and the HV longitudinal acceleration in the first lane change process is as follows:

wherein, a_hvIndicating HV longitudinal acceleration during the first lane change.

S206: calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

S3: and establishing an accelerated overtaking model according to the HV motion state after the first lane change is finished, and calculating accelerated overtaking time and constant-speed overtaking time based on the established accelerated overtaking model.

In the embodiment of the invention, the accelerated overtaking time and the uniform speed overtaking time are calculated, and the specific calculation steps comprise:

s301: calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

S302: and calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Showing the relative distance between HV and RV-1 after the first lane change is completed. When the velocity of HV is less than RV-1, the minimum spacing between HV and RV-1 is 0.

S303: calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a constant speed overtaking time.

S4: calculating to obtain the minimum longitudinal safe distance between the HV and the RV-1 after overtaking according to the HV motion state after overtaking and the established lane change safe distance model;

in the embodiment of the invention, the minimum longitudinal safe distance between HV and RV-1 after overtaking is obtained by calculation, and the calculation process is as follows:

s401: and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass. And (4) considering the influence of time delay and positioning accuracy, and calculating to obtain the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane change process.

S402: according to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

in order to solve the minimum lane change safety distance for returning to the original lane by HV second lane change, the following steps are carried out:

when S is_slc(t) > 0, so as to ensure no collision in the second lane change process

Wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td。S_slc(t₂) The minimum value of (a) is the safe distance that HV and RV-1 do not collide when changing lanes, and can be obtained as follows:

s403: and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking. And solving the error distance according to the GPS positioning precision and the time delay, and then calculating to obtain the minimum longitudinal safety distance during the second lane change.

Due to the overtaking process, the HV initial velocity v is obtained in the second lane change process_hv(t₂) Greater than or equal to RV-1 initial velocity v_rv1(t₂). When the lane change is completed, the HV is the same as the RV-1 speed.

S5: and establishing a reverse overtaking safe distance model according to a multi-vehicle motion mechanism and a lane change safe distance model in the reverse overtaking process, and calculating to obtain the HV reverse overtaking longitudinal minimum safe distance based on the established reverse overtaking safe distance model.

In the embodiment of the invention, the HV reverse overtaking longitudinal minimum safety distance is obtained by calculation, and the specific calculation steps comprise:

s501: and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

s502: after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) represents the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of the target lane after the HV completes the first lane change;

s503: after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

s504: calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

s6: and judging whether reverse overtaking safety risks exist at present or not according to the current multi-vehicle motion state, the minimum longitudinal safety distance and the HV reverse overtaking longitudinal minimum safety distance, and performing early warning. The reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV,RV1)If so, the lane change collision risk exists, otherwise, the lane change collision risk does not exist; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

The reverse overtaking early warning method under the V2X vehicle networking environment is characterized in that basic safety attribute information of multiple vehicles under a reverse overtaking scene is obtained based on V2V information interaction, necessary motion states and vehicle static attribute data are extracted, a lane change safety distance model is combined on the basis of considering system time delay and positioning accuracy, a complex reverse overtaking process is resolved into four processes of switching to a target lane, accelerating overtaking, constant-speed overtaking and switching to an original lane through analysis of a multi-vehicle motion mechanism, an integrated reverse overtaking model is built, and accurate identification of complex reverse overtaking risks is achieved.

The reverse overtaking early warning system under the V2X vehicle networking environment comprises a multi-vehicle target state extraction module, a first lane change safety distance calculation module, an acceleration overtaking calculation module, a second lane change safety distance calculation module, a reverse overtaking safety distance calculation module and a reverse overtaking safety early warning module.

In the embodiment of the invention, the minimum longitudinal safe distance during the first lane change is calculated, and the specific calculation process comprises the following steps:

calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Denotes RV-1 body length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIndicating completionThreshold value of time length required for the first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1;

according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yDenotes the duration of the lateral shift of the HV, τ denotes the time of the lateral shift of the HV, h denotes the lateral shift distance of the HV at the completion of the first lane change, y_hv(t) represents the lateral displacement of HV during the lane change;

according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

wherein S is_flc(t) represents the relative distance between HV and RV-1 at time t during the lane change, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of HV, a_rv1(τ) represents the instantaneous acceleration of RV-1, λ represents the integral variable;

the initial time of the first lane change is HV and RV-1Relative distance S of vehicle_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount, S, of HV at the initial time_flc(t₀) The minimum value of (a) is the minimum longitudinal safety distance in the first lane change;

calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

In the embodiment of the invention, the accelerated overtaking time and the uniform overtaking time are calculated, and the specific calculation process comprises the following steps:

calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

And calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Represents the relative distance between HV and RV-1 after the first lane change is finished;

calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a uniform overtaking time, SD_slc(HV, RV1) represents the minimum longitudinal safety distance between HV and RV-1 after the completion of the overtaking.

In the embodiment of the invention, the minimum longitudinal safe distance between HV and RV-1 after overtaking is obtained by calculation, and the calculation process is as follows:

and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass；

According to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking.

In the embodiment of the invention, the HV reverse overtaking longitudinal minimum safety distance is obtained by calculation, and the specific calculation steps comprise:

and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) shows the acceleration to the maximum speed of the target lane after the HV completes the first lane change, and the acceleration is compared with RV-2A relative movement distance;

after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

the reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV, RV1), there is a lane change collision risk, otherwise it is not present; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

Claims (10)

1. A reverse overtaking early warning method in a V2X vehicle networking environment is characterized by comprising the following steps:

acquiring and analyzing a V2X communication message set to obtain motion states of HV, RV-1 and RV-2;

establishing a lane change safe distance model, and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model;

establishing an accelerated overtaking model according to the HV motion state after the first lane change is finished, and calculating accelerated overtaking time and constant-speed overtaking time based on the established accelerated overtaking model;

calculating to obtain the minimum longitudinal safe distance between the HV and the RV-1 after overtaking according to the HV motion state after overtaking and the established lane change safe distance model;

establishing a reverse overtaking safe distance model according to a multi-vehicle motion mechanism and a lane change safe distance model in the reverse overtaking process, and calculating to obtain an HV reverse overtaking longitudinal minimum safe distance based on the established reverse overtaking safe distance model;

and judging whether reverse overtaking safety risks exist at present or not according to the current multi-vehicle motion state, the minimum longitudinal safety distance and the HV reverse overtaking longitudinal minimum safety distance, and performing early warning.

2. The reverse overtaking early warning method in the V2X car networking environment as recited in claim 1, wherein the calculating the minimum longitudinal safe distance for the first lane change includes:

calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Denotes RV-1 body length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIndicating a threshold value of the time required for completing the first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1;

according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yDenotes the duration of the lateral shift of the HV, τ denotes the time of the lateral shift of the HV, h denotes the lateral shift distance of the HV at the completion of the first lane change, y_hv(t) represents the lateral displacement of HV during the lane change;

according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

t∈(t₀+T_lc,t₀+T_long)

wherein S is_flc(t) represents the relative distance between HV and RV-1 at time t during the lane change, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of HV, a_rv1(τ) represents the instantaneous acceleration of RV-1, λ represents the integral variable;

relative distance S between two vehicles HV and RV-1 at initial lane change time for the first time_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount, S, of HV at the initial time_flc(t₀) The minimum value of (a) is the minimum longitudinal safety distance in the first lane change;

calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

3. The reverse overtaking early warning method under the V2X car networking environment as claimed in claim 2, wherein the calculating step comprises:

calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

And calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Represents the relative distance between HV and RV-1 after the first lane change is finished;

calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a constant speed overtaking time.

4. The reverse overtaking early warning method in V2X car networking environment as recited in claim 3, wherein the minimum longitudinal safe distance between HV and RV-1 after overtaking completion is obtained by calculation, and the calculation process is as follows:

and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass；

According to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

t∈(t₂+T_lc,t₂+T_long)

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking.

5. The reverse overtaking warning method in V2X car networking environment as recited in claim 4,

the calculation is carried out to obtain the HV reverse overtaking longitudinal minimum safe distance, and the specific calculation steps comprise:

and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) represents the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of the target lane after the HV completes the first lane change;

after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

the reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV, RV1), there is a lane change collision risk, otherwise it is not present; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

6. The utility model provides a reverse overtaking early warning system under V2X car networking environment which characterized in that includes:

the multi-vehicle target state extraction module is used for acquiring and analyzing a V2X communication message set to obtain motion states of HV, RV-1 and RV-2;

the first lane change safe distance calculation module is used for establishing a lane change safe distance model and calculating the minimum longitudinal safe distance during the first lane change according to the established lane change safe distance model;

the acceleration overtaking calculation module is used for establishing an acceleration overtaking model according to the HV motion state after the first lane change is finished, and calculating acceleration overtaking time and constant-speed overtaking time based on the established acceleration overtaking model;

the second lane change safe distance calculation module is used for calculating and obtaining the minimum longitudinal safe distance between the HV and the RV-1 after the overtaking is finished according to the HV motion state after the overtaking is finished and the established lane change safe distance model;

the reverse overtaking safety distance calculation module is used for establishing a reverse overtaking safety distance model according to a multi-vehicle motion mechanism and a lane change safety distance model in the reverse overtaking process, and calculating to obtain an HV reverse overtaking longitudinal minimum safety distance based on the established reverse overtaking safety distance model;

and the reverse overtaking safety early warning module is used for judging whether reverse overtaking safety risks exist at present or not according to the current multi-vehicle motion state, the minimum longitudinal safety distance and the HV reverse overtaking longitudinal minimum safety distance and carrying out early warning.

7. The reverse overtaking warning system under V2X car networking environment as claimed in claim 6, wherein the calculation of the minimum longitudinal safe distance for the first lane change includes:

calculating to obtain the position relation and the collision time condition that HV and RV-1 do not collide in the first lane change process, wherein the calculation formula is as follows:

wherein x is_hv(t) represents the longitudinal displacement of HV at time t, x_rv1(t) represents the longitudinal displacement of RV-1 at time t, D_errRepresents the longitudinal relative distance error between HV and RV-1, d_tdRepresenting the relative distance error due to the delay response, L_rv1Denotes RV-1 body length, W_hvShowing the width of the HV vehicle body, theta (T) showing the angle between the tangent direction of the HV track and the longitudinal direction of the road at time T, T_longIndicating a threshold value of the time required for completing the first lane change, t₀Indicates the initial time, T_lcIndicating that the first lane change process is started from the initial time and passes through the time T_lcHV collides with RV-1;

according to the change of the lateral acceleration of the automobile in the first lane changing process and the width of the road, the collision time of the collision condition in the lane changing process is calculated, and the calculation formula is as follows:

wherein, a_hv,y(T) represents the lateral acceleration of HV during the first lane change, T_hv,yDenotes the duration of the lateral shift of the HV, τ denotes the time of the lateral shift of the HV, h denotes the lateral shift distance of the HV at the completion of the first lane change, y_hv(t) represents the lateral displacement of HV during the lane change;

according to the change of the longitudinal speed and the acceleration of the HV and the RV-1 in the first lane changing process, establishing a relative distance change formula of the HV and the RV-1 in the lane changing process:

t∈(t₀+T_lc,t₀+T_long)

wherein S is_flc(t) shows the relative relationship of the HV and RV-1 vehicles at time t during the lane changeDistance, S_flc(t₀) Indicates the relative distance between two vehicles, a, HV and RV-1 at the initial lane change time_rv1Represents the acceleration of RV-1 at time τ, a_hvRepresents the acceleration, v, of HV at time τ_rv1(t₀) Represents the longitudinal displacement, v, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount of HV at the initial time, a_hv(τ) represents the instantaneous acceleration of HV, a_rv1(τ) represents the instantaneous acceleration of RV-1, λ represents the integral variable;

relative distance S between two vehicles HV and RV-1 at initial lane change time for the first time_flc(t₀) Satisfies the following conditions:

S_flc(t₀)＝x_rv1(t₀)-x_hv(t₀)-L_hv-D_err-d_td

wherein x is_rv1(t₀) Denotes the longitudinal displacement, x, of RV-1 at the initial time_hv(t₀) Represents the longitudinal displacement amount, S, of HV at the initial time_flc(t₀) The minimum value of (a) is the minimum longitudinal safety distance in the first lane change;

calculating to obtain the minimum longitudinal safe distance during the first lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_flc(HV, RV1) represents the minimum longitudinal safety distance on the first lane change.

8. The reverse overtaking early warning system under V2X car networking environment as claimed in claim 7, wherein the specific calculation process comprises:

calculating the acceleration overtaking time of the HV accelerated to the speed of the target lane after the first lane change is finished, wherein the calculation formula is as follows:

wherein, T_accIndicating accelerated overtaking time, v_hv(t₁) Represents the time t₁The longitudinal displacement of the plunger tip, t₁Satisfy t₁＝t₀+T_long+T_acc，a_maxRepresenting the maximum acceleration of the HV.

And calculating the relative distance between the HV and the RV-1 after the first lane change is finished, wherein the calculation formula is as follows:

wherein RD_hv,rv1(t₀+T_long) Represents the relative distance between HV and RV-1 after the first lane change is finished;

calculating the constant-speed overtaking time after the HV lane change to the target lane, wherein the calculation formula is as follows:

RD_hv,rv1(t₁)＝RD_hv,rv1(t₀+T_long)+RD_hv,rv1(T_acc)

wherein RD_hv,rv1(t₁) Indicating the relative movement distance between HV and RV-1, RD, after completion of the accelerated overtaking_hv,rv1(t₀+T_long) Indicates the relative movement distance between HV and RV-1, RD, after the first lane change is completed_hv,rv1(T_acc) Represents the relative movement distance, T, between HV and RV-1 during accelerated overtaking_passIndicating a uniform overtaking time, SD_slc(HV, RV1) represents the minimum longitudinal safety distance between HV and RV-1 after the completion of the overtaking.

9. The reverse overtaking warning system under V2X networking environment as claimed in claim 10, wherein the minimum longitudinal safe distance between HV and RV-1 after overtaking completion is calculated by:

and calculating the position relation and the collision time condition that the HV and the RV-1 do not collide in the second lane changing process, wherein the calculation formula is as follows:

wherein, t₂Indicates the HV uniform overtaking completion moment and meets t₂＝t₁+T_pass；

According to the changes of the longitudinal speed and the acceleration of the HV and the RV-1 in the second track changing process, establishing a relative distance change formula of the HV and the RV-1 in the track changing process:

t∈(t₂+T_lc,t₂+T_long)

wherein S is_slc(t₂)＝x_hv(t₂)-x_rv1(t₂)-L_hv-D_err-d_td，x_rv1(t₂) Represents the time t₂Longitudinal displacement of time RV-1, x_hv(t₂) Represents the time t₂The longitudinal displacement amount of the HV;

and calculating to obtain the minimum longitudinal safe distance during the second lane change, wherein the expression formula of the minimum longitudinal safe distance during the first lane change is as follows:

wherein, SD_slc(HV, RV1) represents the minimum longitudinal safety distance after completion of the overtaking.

10. The reverse overtaking warning system as recited in claim 9 in the environment of V2X car networking,

the calculation is carried out to obtain the HV reverse overtaking longitudinal minimum safe distance, and the specific calculation steps comprise:

and calculating the relative movement distance between the HV and the RV-2 in the first track changing process of the HV, wherein the calculation formula is as follows:

wherein D is₁(HV, RV2) represents the relative movement distance, v, from RV-2 during the first pass of the HV_rv2(t₀) Represents the longitudinal displacement of RV-2 at the initial time;

after the HV finishes the first lane change, the relative movement distance between the HV and the RV-2 is calculated in the process of accelerating to the maximum speed of the target lane, and the calculation formula is as follows:

wherein D is₂(HV, RV2) represents the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of the target lane after the HV completes the first lane change;

after the HV accelerates to the speed of the target lane, the relative movement distance between the HV and the RV-2 within the uniform speed overtaking time is calculated, and the calculation formula is as follows:

D₃(HV,RV2)＝[v_hv(t₁)+v_rv2(t₀)]*T_pass

wherein D is₃(HV, RV2) represents the relative movement distance with RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane;

calculating to obtain the HV reverse overtaking longitudinal minimum safety distance according to the relative movement distance between the HV and the RV-2 in the first track switching process of the HV, the relative movement distance between the HV and the RV-2 in the process of accelerating to the maximum speed of a target lane after the HV completes the first track switching, and the relative movement distance between the HV and the RV-2 in the uniform speed overtaking time after the HV accelerates to the speed of the target lane, wherein the calculation formula is as follows:

wherein SD (HV, RV2) represents the HV reverse overtaking longitudinal minimum safety distance;

the reverse overtaking safety risk comprises lane change collision risk and overtaking collision risk, if x_rv1(t₀)-x_hv(t₀)≥SD_flc(HV, RV1), there is a lane change collision risk, otherwise it is not present; if x_rv2(t₀)-x_hv(t₀) And if the current value is more than or equal to SD (HV, RV2), the overtaking collision risk exists, otherwise, the overtaking collision risk does not exist.

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