阅读说明：本技术 一种基于自动驾驶的变道避障方法与系统 (Lane changing and obstacle avoiding method and system based on automatic driving ) 是由 熊锐剑 于 2021-07-26 设计创作，主要内容包括：本发明涉及自动驾驶技术领域,提供一种基于自动驾驶的变道避障方法与系统,包括感知模块、识别模块、路径计算模块、导航模块、风险判断模块、行驶控制模块、数据库,在判断到本车需要变道时,获取并识别周围的行车环境数据,在规划出变道路径时,通过行车环境数据获取在变道判断区间内目标障碍物的运动区域,进而根据预设条件计算出运动区域是否会与预期变道路径中的本车发生重叠(碰撞),从而确定是否可以实施变道,其中运动区域、变道路径的计算简单,但却可有效的识别到各个车道上的动态障碍物,从而保证行车安全性。(The invention relates to the technical field of automatic driving, and provides a lane changing and obstacle avoiding method and system based on automatic driving, which comprises a sensing module, an identification module, a path calculation module, a navigation module, a risk judgment module, a driving control module and a database.)

1. A lane changing and obstacle avoiding method based on automatic driving is characterized by comprising the following steps:

s1, when judging that the vehicle needs to change lanes, acquiring driving environment data around the vehicle;

s2, acquiring the driving state of the vehicle and planning a lane change path;

s3, determining a corresponding lane change judgment interval according to the lane change path, and acquiring a movement area of a target obstacle in the lane change judgment interval according to the driving environment data;

and S4, judging whether the lane change of the vehicle has collision risk according to preset conditions, the lane change path and the motion area, and determining whether to execute the lane change path according to the judgment result.

2. The lane-changing obstacle-avoiding method based on automatic driving as claimed in claim 1, wherein in said step S1:

the judgment basis of the lane change of the vehicle is that the running speed of the vehicle is greater than that of a front vehicle in the same lane, and the distance between the two vehicles reaches a first threshold value;

the method for acquiring the driving environment data around the vehicle is as follows: a coordinate system is established by taking a near side lane line of a target lane as a Y axis and taking a straight line passing through the geometric center of the current vehicle as an X axis, and driving environment data including vehicle data of the target vehicle on the lane where the vehicle is located and the adjacent lane are further acquired by adopting a sensing element, wherein the vehicle data include an instant position, an instant speed and vehicle body data.

3. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 1, wherein the step S2 includes the steps of:

s21, acquiring the current driving state of the vehicle, including the driving speed, the driving acceleration and the transverse distance between the vehicle and the target lane;

and S22, determining all selectable turning radii according to the driving speed, and further planning a corresponding lane change path by combining the driving acceleration and the transverse distance.

4. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 2, wherein the step S3 includes the steps of:

s31, determining a lane change judgment interval for executing lane change and obstacle avoidance by the vehicle according to the lane change path, the driving speed and the driving acceleration;

s32, calculating the motion trail of the target vehicle in the lane change judgment section according to the instant position and the instant speed of the target vehicle;

s33, calculating a motion area of a corresponding target obstacle according to the motion trail of the target vehicle and the vehicle body data;

the lane change judgment interval is a time interval during which the vehicle performs lane change, or a time interval between the vehicle entering the target lane and the completion of lane change.

5. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 1, wherein the step S4 includes the steps of:

s41, obtaining mark coordinates of a preset mark bit on the vehicle in the lane change judgment interval from all lane change paths with the driving acceleration of 0, comparing the mark coordinates with the motion area, judging whether the lane change paths without collision risks exist according to preset conditions, if so, selecting a target lane change path from all executable lane change paths according to preset rules and executing, and if not, entering the next step;

s42, obtaining mark coordinates of a preset mark bit on the vehicle in the lane change judgment interval from all the lane change paths with the driving acceleration larger than 0, comparing the mark coordinates with the motion area, judging whether the lane change paths without collision risks exist according to the preset conditions, if so, selecting a target lane change path from all the executable lane change paths according to preset rules and executing the target lane change path, and if not, forbidding the lane change operation.

6. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 5, wherein said step S41 includes the steps of:

A. acquiring all lane change paths with the driving acceleration of 0, and calculating mark coordinates of preset mark positions on the vehicle in each lane change path in the lane change judgment interval according to vehicle body data of the vehicle;

B. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

C. judging whether at least one group of the first distance and the second distance is always larger than a preset condition, if so, judging that no collision risk exists and acquiring the corresponding executable turning radius, and entering the next step, otherwise, judging that the collision risk exists and entering the step S42;

D. and acquiring a target turning radius from all the executable turning radii according to a preset rule, and executing the corresponding lane change path.

7. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 5, wherein said step S42 includes the steps of:

E. acquiring all lane change paths with the driving acceleration larger than 0, and calculating mark coordinates of preset mark positions on the vehicle in each lane change path in the lane change judgment interval according to vehicle body data of the vehicle;

F. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

G. judging whether a group of first distances and second distances always meet preset conditions, if so, judging that no collision risk exists and obtaining corresponding executable turning radii to enter the next step, otherwise, forbidding lane change operation and decelerating to return to the step S1 or finishing the lane change planning;

H. and acquiring a target turning radius from all the executable turning radii according to a preset rule, and executing the corresponding lane change path.

8. The lane-changing and obstacle-avoiding method based on automatic driving as claimed in claim 4, wherein the preset marks comprise: taking the most protruding part at the front end of the vehicle close to one side of the target lane as a first marker bit, and taking the most protruding part at the rear end of the vehicle close to one side of the target lane as a second marker bit;

the preset conditions are as follows: the difference between the first zone bit coordinate and the coordinate of each characteristic point of the target vehicle is greater than a first threshold value, the difference between the second zone bit coordinate and the coordinate of each characteristic point of the target vehicle is greater than a second threshold value, and the distance between the vehicle and the front vehicle in the same lane is greater than a third threshold value;

the body data includes a body length and a body width.

9. The utility model provides a lane change keeps away barrier system based on autopilot which characterized in that: the system comprises a sensing module, an identification module, a path calculation module, a navigation module, a risk judgment module, a driving control module and a database;

the sensing module is used for acquiring driving environment data;

the identification module is used for identifying the driving environment data and determining the surrounding road condition and the vehicle data of the target vehicle;

the database is used for storing vehicle characteristic data;

the path calculation module is used for calculating the motion area of the target vehicle at any moment according to the vehicle data and the vehicle characteristic data;

the navigation module is used for planning a lane change path according to the road condition;

the risk judgment module is used for judging whether collision risk exists in the lane change of the vehicle according to preset conditions, the lane change path and the motion area, and determining whether the lane change path is executed according to a judgment result;

and the driving control module is used for receiving the control instruction of the risk judgment module and executing the lane changing path or forbidding lane changing operation.

10. The lane-changing obstacle-avoiding system based on automatic driving as claimed in claim 9, wherein:

the perception system comprises a radar and an image acquisition component;

the road condition comprises a traffic sign, and the traffic sign comprises a lane line, a traffic sign and a traffic signal lamp;

the vehicle characteristic data comprises wind resistance of the vehicle in different speed modes, wheel resistance under different load and road conditions, and corresponding relation between accelerator opening and speed change ratio and power output.

Technical Field

The invention relates to the technical field of automatic driving, in particular to a lane changing and obstacle avoiding method and system based on automatic driving.

Background

In the process of driving on public roads, vehicles often need to change lanes in order to improve traffic efficiency or avoid obstacles on the driving lanes. However, since the driving positions of other vehicles on adjacent lanes change at any moment, when an automatically driven vehicle changes lanes, the positions of surrounding static or dynamic obstacles must be observed at any moment, so as to ensure that the vehicle does not collide with other vehicles, pedestrians or other obstacles in the lane changing process, and ensure the driving safety.

In the prior art, several vehicle obstacle avoidance schemes are designed, for example:

1) the invention patent with publication number CN109540159B discloses a method for obtaining curvature of a path by using a speed planning method and obtaining a smooth path by fitting a B-spline curve or a bezier curve.

2) The invention patent publication CN109910878B discloses a differential steering method for building an optimal trajectory optimization model using polynomial fitting curves to avoid obstacles.

However, for the identification of other vehicles moving in the vehicle driving environment by the above two vehicle obstacle avoidance schemes, the proposed path planning scheme is too complex to calculate, and does not consider the instant positions of other vehicles driving on the road, so that the two vehicle obstacle avoidance schemes cannot adapt to the road driving environment which is changeable instantly, and the driving safety cannot be ensured.

Disclosure of Invention

The invention provides a lane changing and obstacle avoiding method and system based on automatic driving, and solves the technical problems that an existing vehicle obstacle avoiding scheme is too complex in path planning scheme calculation, dynamic obstacles on a lane cannot be effectively identified, and driving safety cannot be guaranteed.

In order to solve the technical problems, the invention provides a lane changing and obstacle avoiding method based on automatic driving, which comprises the following steps:

s1, when judging that the vehicle needs to change lanes, acquiring driving environment data around the vehicle;

s2, acquiring the driving state of the vehicle and planning a lane change path;

s3, determining a corresponding lane change judgment interval according to the lane change path, and acquiring a movement area of a target obstacle in the lane change judgment interval according to the driving environment data;

and S4, judging whether the lane change of the vehicle has collision risk according to preset conditions, the lane change path and the motion area, and determining whether to execute the lane change path according to the judgment result.

According to the basic scheme, when the lane change is judged to be needed by the vehicle, the surrounding driving environment data are acquired and recognized, when the lane change path is planned, the movement area of the target obstacle in the lane change judgment section is acquired through the driving environment data, and whether the movement area is overlapped (collided) with the vehicle in the expected lane change path or not is calculated according to preset conditions, so that whether the lane change can be implemented or not is determined, the calculation of the movement area and the lane change path is simple, but the dynamic obstacles on each lane can be effectively recognized, and the driving safety is guaranteed.

In further embodiments, in said step S1:

the judgment basis of the lane change of the vehicle is that the running speed of the vehicle is greater than that of a front vehicle in the same lane, and the distance between the two vehicles reaches a first threshold value;

the method for acquiring the driving environment data around the vehicle is as follows: a coordinate system is established by taking a near side lane line of a target lane as a Y axis and taking a straight line passing through the geometric center of the current vehicle as an X axis, and driving environment data including vehicle data of the target vehicle on the lane where the vehicle is located and the adjacent lane are further acquired by adopting a sensing element, wherein the vehicle data include an instant position, an instant speed and vehicle body data.

According to the scheme, the near side (namely, the side close to the vehicle) lane line of the target lane is used as the Y axis, the straight line passing through the geometric center of the current vehicle is used as the X axis to establish a coordinate system, the surrounding environment is identified and positioned, the actual distance between the surrounding target obstacles and the vehicle can be directly obtained, and therefore the calculation efficiency can be improved, and the risk prediction efficiency of lane change collision can be improved.

In further embodiments, the step S2 includes the steps of:

s21, acquiring the current driving state of the vehicle, including the driving speed, the driving acceleration and the transverse distance between the vehicle and the target lane;

and S22, determining all selectable turning radii according to the driving speed, and further planning a corresponding lane change path by combining the driving acceleration and the transverse distance.

According to the scheme, aiming at the spatial freedom degree of lane changing, all selectable turning radii based on the current driving speed are predetermined to plan a corresponding lane changing path, so that all obstacle avoidance possibilities are covered, and the driving safety of a user is guaranteed as much as possible.

In further embodiments, the step S3 includes the steps of:

s31, determining a lane change judgment interval for executing lane change and obstacle avoidance by the vehicle according to the lane change path, the driving speed and the driving acceleration;

s32, calculating the motion trail of the target vehicle in the lane change judgment section according to the instant position and the instant speed of the target vehicle;

and S33, calculating the movement area of the corresponding target obstacle according to the movement track of the target vehicle and the vehicle body data.

The lane change judgment interval is a time interval during which the vehicle performs lane change, or a time interval between the vehicle entering the target lane and the completion of lane change.

According to the lane change path, the driving speed and the driving acceleration, the time node of the vehicle entering the target lane is calculated to serve as the lane change judgment section, the collision risk of the lane change judgment section is calculated, the time node can effectively judge the collision risk of the vehicle in the whole lane change path, and the risk prediction efficiency is improved.

In further embodiments, the step S4 includes the steps of:

s41, obtaining mark coordinates of a preset mark bit on the vehicle in the lane change judgment interval from all lane change paths with the driving acceleration of 0, comparing the mark coordinates with the motion area, judging whether the lane change paths without collision risks exist according to preset conditions, if so, selecting a target lane change path from all executable lane change paths according to preset rules and executing, and if not, entering the next step;

s42, obtaining mark coordinates of a preset mark bit on the vehicle in the lane change judgment interval from all the lane change paths with the driving acceleration larger than 0, comparing the mark coordinates with the motion trail, judging whether the lane change paths without collision risks exist according to the preset conditions, if so, selecting a target lane change path from all the executable lane change paths according to preset rules and executing the target lane change path, and if not, forbidding the lane change operation.

According to the scheme, according to the actual lane changing situation of the vehicle, path prediction covering the lane changing situation of a constant speed lane changing (the acceleration is 0) and an accelerated lane changing (the acceleration is greater than 0) is designed, preset conditions are preset to screen executable paths from all lane changing paths, then an optimal target lane changing path is selected according to preset rules, and the lane changing execution effect of the vehicle is further optimized.

In further embodiments, the step S41 includes the steps of:

A. acquiring all lane change paths with the driving acceleration of 0, and calculating mark coordinates of preset mark positions on the vehicle in each lane change path in the lane change judgment interval according to vehicle body data of the vehicle;

B. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

C. judging whether at least one group of the first distance and the second distance always meet preset conditions, if so, judging that no collision risk exists and acquiring the corresponding executable turning radius, and entering the next step, otherwise, judging that the collision risk exists, and entering a step S42;

D. and acquiring a target turning radius from all the executable turning radii according to a preset rule, and executing the corresponding lane change path.

In further embodiments, the step S42 includes the steps of:

E. acquiring all lane change paths with the driving acceleration larger than 0, and calculating mark coordinates of preset mark positions on the vehicle in each lane change path in the lane change judgment interval according to vehicle body data of the vehicle;

F. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

G. judging whether a group of first distances and second distances always meet preset conditions, if so, judging that no collision risk exists, acquiring corresponding executable turning radii, entering the next step, otherwise, forbidding lane change operation, decelerating and returning to the step S1 or finishing the lane change planning;

H. and acquiring a target turning radius from all the executable turning radii according to a preset rule, and executing the corresponding lane change path.

According to the scheme, the mark coordinates of the preset mark bit on the vehicle in each lane change path in the lane change judgment interval are obtained, the preset mark bit is used as a collision prediction point, the first distance between the preset mark bit and all motion areas and the second distance between the vehicle and a front vehicle in the same lane at the moment are calculated through the mark coordinates, the preset threshold value is compared, and the lane change risk of the corresponding lane change path can be quickly and visually reflected through data comparison, so that the lane change obstacle avoidance prediction efficiency is greatly improved; and acquiring a target turning radius from all executable turning radii according to a preset rule, executing a corresponding lane change path, and giving the user the best use experience.

The preset mark comprises: taking the most protruding part at the front end of the vehicle close to one side of the target lane as a first marker bit, and taking the most protruding part at the rear end of the vehicle close to one side of the target lane as a second marker bit;

the preset conditions are as follows: the preset conditions are as follows: the difference between the first marker coordinate and the coordinate of each characteristic point of the target vehicle is larger than a first threshold value, the difference between the second marker coordinate and the coordinate of each characteristic point of the target vehicle is larger than a second threshold value, and the distance between the vehicle and the front vehicle in the same lane is larger than a third threshold value.

The body data includes a body length and a body width.

According to the scheme, the most protruding part at the front end of the vehicle close to the target lane and the most protruding part at the rear end of the vehicle close to the target lane are used as key nodes for determining the prediction of the lane change collision of the vehicle, so that the collision risk of the vehicle in the whole lane change path can be effectively judged, and the risk prediction efficiency is improved.

The invention also provides a lane changing and obstacle avoiding system based on automatic driving, which comprises a sensing module, an identification module, a path calculation module, a navigation module, a risk judgment module, a driving control module and a database;

the sensing module is used for acquiring driving environment data;

the identification module is used for identifying the driving environment data and determining the surrounding road condition and the vehicle data of the target vehicle;

the database is used for storing vehicle characteristic data;

the path calculation module is used for calculating the motion area of the target vehicle at any moment according to the vehicle data and the vehicle characteristic data;

the navigation module is used for planning a lane change path according to the road condition;

the risk judgment module is used for judging whether collision risk exists in the lane change of the vehicle according to preset conditions, the lane change path and the motion area, and determining whether the lane change path is executed according to a judgment result;

and the driving control module is used for receiving the control instruction of the risk judgment module and executing the lane changing path or forbidding lane changing operation.

In a further embodiment, the perception system comprises a radar and an image acquisition component;

the road condition comprises a traffic sign, and the traffic sign comprises a lane line, a traffic sign and a traffic signal lamp;

the vehicle characteristic data comprises wind resistance of the vehicle in different speed modes, wheel resistance under different load and road conditions, and corresponding relation between accelerator opening and speed change ratio and power output.

This scheme adopts simple radar and image acquisition subassembly, and the perception system of group construction acquires driving environment data, low cost, and the computational efficiency of collision risk is high.

Drawings

Fig. 1 is a work flow chart of a lane changing and obstacle avoiding method based on automatic driving according to embodiment 1 of the present invention;

fig. 2 is a schematic diagram of path planning provided in embodiment 1 of the present invention;

fig. 3 is a system framework diagram of an automatic driving-based lane-changing and obstacle-avoiding system according to embodiment 2 of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which are given solely for the purpose of illustration and are not to be construed as limitations of the invention, including the drawings which are incorporated herein by reference and for illustration only and are not to be construed as limitations of the invention, since many variations thereof are possible without departing from the spirit and scope of the invention.

Example 1

As shown in fig. 1 and 2, the lane changing and obstacle avoiding method based on automatic driving in the embodiment of the present invention includes steps S1 to S4:

s1, judging the vehicle M₀And when lane changing is required, acquiring driving environment data around the lane changing device.

In the present embodiment, the host vehicle M₀The judgment basis of the lane change is that the vehicle M₀The running speed of the vehicle is higher than that of the front vehicle M on the same lane_FAnd the distance between the two vehicles reaches a first threshold value;

the method for acquiring the driving environment data around the vehicle comprises the following specific steps: the near side (i.e. the side close to the vehicle) lane line of the target lane is taken as the Y axis to pass through the current vehicle M₀The straight line of the geometric center is used as an X axis to establish a coordinate system, and then a sensing element is adopted to acquire driving environment data, including the vehicle M₀And vehicle data of the target vehicle on the lane and the adjacent lane, wherein the vehicle data comprises an instant position, an instant speed and vehicle body data.

For example, with the host vehicle M₀The left lane line (here, the obstacle avoidance prediction for only the left lane; if the obstacle avoidance prediction for the right lane, the right lane line is selected) is used as the Y axis to pass through the vehicle M₀And a straight line which is perpendicular to the geometric center and the Y axis is the X axis, and an Euclidean coordinate system is established.

Preferably, the sensing elements include, but are not limited to, radar and cameras, which may monitor the host vehicle M in real time₀Front vehicle M on the same lane_FAnd all target vehicles on adjacent lanes, comprising: vehicle M with negative Y value on left lane_LNVehicle M with negative Y value on right lane_RN(ii) a Vehicle M with zero or positive Y value on right lane_LPVehicle M with zero or positive Y value in right lane_RP。

In order to reduce the system calculation amount and improve the system real-time performance, the target vehicle is optimized, and the optimized target vehicle of the left lane is as follows: vehicle M with negative Y value nearest to the vehicle on left lane_LN1Vehicle M with zero or positive Y value nearest to the vehicle on left lane_LP1And a vehicle M_LP1Front vehicle M_LP2(i.e., M)_LP2At M_LP1Right front travel).

Similarly, the preferred target vehicles for the right lane are: vehicle M with negative Y value nearest to the vehicle on right lane_RN1Vehicle M with zero or positive Y value nearest to the vehicle on left lane_RP1And a vehicle M_RP1Front vehicle M_RP2(i.e., M)_RP2At M_RP1Right front travel).

The present embodiment takes the lane line of the near side (i.e., the side close to the host vehicle) of the target lane as the Y-axis to pass through the current host vehicle M₀The straight line of the geometric center is used as an X axis to establish a coordinate system, the surrounding environment is identified and positioned, and the surrounding target obstacles and the vehicle M can be directly obtained₀Thereby improving the calculation efficiency and improving the risk prediction efficiency of lane change collision.

S2, obtaining the vehicle M₀The method for planning lane change path comprises the following steps of S21-S22:

s21, obtaining the vehicle M₀Current lineThe vehicle state comprises the driving speed, the driving acceleration and the transverse distance between the target lane and the vehicle;

and S22, determining all selectable turning radii according to the driving speed, and further planning a corresponding lane change path by combining the driving acceleration and the transverse distance.

In the present embodiment, lane change is from the host vehicle M₀The middle position of the lane is changed to the middle position of the target lane, so that the vehicle M₀The lateral distance from the target lane is preferably the lane width D.

In the present embodiment, the host vehicle M₀Current vehicle speed V_M0And selecting the turning radius R of the vehicle which gives consideration to safety and comfort.

For example:

when the speed V is_M0At a speed of 30 km/h or less, the turning radius of the vehicle M₀Is the first choice R1, and a fixed value m is added to the second choice R2, i.e. the turning radius of the second choice is: r2 ═ R1+ m; then increasing the turning radius by m on the basis of the second selection as a third selection: r3 ═ R1+2 m; and sequentially carrying out class pushing to a fifth selection: r5 ═ R1+4 m.

When the speed V is_M0At 30-70 km/h, the vehicle M₀The set first turning radius R6 is a fixed value n added to the fifth choice R5, namely: r6 ═ R5+ n; and so on, R10 ═ R5+5 n.

When the speed V is_M0And if the turning radius exceeds 70 km/h, selecting the first turning radius as follows: r11 ═ R10+ p; the turning radii selected in turn, R12 ═ R10+2p, until R15 ═ R10+4 p.

In the embodiment, all selectable turning radii based on the current driving speed are predetermined according to the spatial degree of freedom of lane changing so as to plan a corresponding lane changing path, thereby covering all obstacle avoidance possibilities and ensuring the driving safety of a user as much as possible.

S3, determining a corresponding lane change judgment interval according to the lane change path, and acquiring a movement area of a target obstacle in the lane change judgment interval according to the driving environment data, wherein the method comprises the following steps of S31-S33:

s31, determining the vehicle M according to the lane change path, the driving speed and the driving acceleration₀Executing a lane change judgment interval for lane change and obstacle avoidance;

s32, calculating the motion track of the target vehicle in the lane change judgment interval according to the instant position and the instant speed of the target vehicle;

and S33, calculating the motion area of the corresponding target obstacle according to the motion trail of the target vehicle and the vehicle body data.

The lane change judging interval is a time interval for the vehicle to perform lane change or a time interval from the vehicle entering the target lane to the completion of lane change; the body data of the target vehicle comprises the body length and the body width thereof; the motion area of the target obstacle is an area formed by coordinates of each characteristic point (including a left front point, a right front point, a left rear point and a right rear point) of the target vehicle.

In this embodiment, the vehicle M is calculated according to the lane change path, the driving speed and the driving acceleration₀The time node entering the target lane is used as a lane change judgment interval, the collision risk in the lane change judgment interval is calculated, and the time node can effectively judge the vehicle M₀And the collision risk in the whole lane change path improves the risk prediction efficiency.

S4, judging the vehicle M according to the preset conditions, the lane change path and the motion area₀Whether collision risk exists in lane change or not and whether a lane change path is executed or not is determined according to a judgment result, and the method comprises the following steps of S41-S42:

s41, obtaining mark coordinates of a preset mark position on the vehicle in a lane change judgment interval from all lane change paths with the vehicle acceleration of 0, comparing the mark coordinates with a motion area, judging whether the lane change paths without collision risks exist according to preset conditions, if so, selecting a target lane change path from all executable lane change paths according to preset rules and executing, and if not, entering the next step.

Wherein, predetermine the flag bit and include: with the vehicle M₀The most protruded part at the front end of the side close to the target lane is the first mark position P1, so that the vehicle M₀The most protruding part at the rear end close to one side of the target lane is a second marker position P2;

taking the left lane obstacle avoidance as an example, the first marker P1 is the host vehicle M₀The left front portion (e.g., left headlight) and the second flag P2 are left rear portions (e.g., left rear headlight).

The preset conditions are as follows: first flag P1 coordinate (x)_p1,y_p1) With the target vehicle M_LN、M_LPThe difference of the coordinates of each feature point is larger than a first threshold value A, and the coordinate (x) of a second flag bit P2_p2,y_p2) With the target vehicle M_LN、M_LPThe difference of the coordinates of each feature point is larger than a second threshold value B, and the vehicle M₀With the same lane front car M_FIs larger than the third threshold value C.

The first threshold a, the second threshold B, and the third threshold C may be set according to actual conditions.

In the present embodiment, step S41 includes steps a to D:

A. obtaining all lane-changing paths with the driving acceleration of 0 and according to the vehicle M₀Calculates the vehicle M in each lane change path in the lane change judgment section₀Marking coordinates of the preset mark bits are arranged;

B. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

C. judging whether at least one group of first distances and second distances always meet preset conditions, if so, judging that no collision risk exists and obtaining corresponding executable turning radii to enter the next step, otherwise, judging that the collision risk exists and entering the step S42;

D. and acquiring a target turning radius from all executable turning radii according to a preset rule, and executing a corresponding lane change path.

S42, obtaining the vehicle M in the lane change judgment section from all lane change paths with the driving acceleration larger than 0₀And comparing the mark coordinates of the preset mark positions with the motion area, judging whether a lane change path without collision risk exists according to preset conditions, if so, selecting a target lane change path from all executable lane change paths according to preset rules and executing, and if not, forbidding the lane change operation.

In the present embodiment, step S42 includes steps E to H:

E. obtaining all lane-changing paths with the driving acceleration larger than 0, and according to the vehicle M₀Calculates the vehicle M in each lane change path in the lane change judgment section₀Marking coordinates of the preset mark bits are arranged;

F. calculating a first distance and a second distance according to the mark coordinates and the motion area at the corresponding moment;

G. judging whether at least one group of first distance and second distance always meet preset conditions, if so, judging that no collision risk exists, acquiring a corresponding executable turning radius, entering the next step, otherwise, forbidding lane change operation and decelerating, and returning to the step S1 or finishing the lane change planning;

H. and acquiring a target turning radius from all executable turning radii according to a preset rule, and executing a corresponding lane change path.

The embodiment acquires the vehicle M in each lane change path₀Marking coordinates of the preset marking bits are obtained, the preset marking bits are used as collision prediction points, and first distances between the preset marking bits and all motion areas and the vehicle M at the moment are calculated through the marking coordinates₀With the same lane front car M_FThe second distance is compared with a preset threshold value, and the lane change risk corresponding to the lane change path can be quickly and intuitively reflected through data comparison, so that the lane change obstacle avoidance prediction efficiency is greatly improved; and acquiring a target turning radius from all executable turning radii according to a preset rule, executing a corresponding lane change path, and giving the user the best use experience.

Taking the left lane obstacle avoidance as an example, the lane change path is formed by connecting two arc paths with symmetrical centers, and the intersection point of the two arc paths is on the lane line of the near side (i.e. the side close to the vehicle) of the target lane.

The preset flag bits in the above steps S41 and S42 include: host vehicle M₀The most protruded part at the front end of one side close to the target lane is the first marker coordinate P1 (x)_p1,y_p1) A coincidence point when coincident with the target lane line; and, the host vehicle M₀The most protruded part at the rear end of one side close to the target lane is a second marker coordinate P2 (x)_p2,y_p2) The specific calculation formula is as follows:

wherein (X)_M0,Y_M0) For the vehicle M₀The coordinate value of the geometric center point of (a) at any time t; l is_M0Is the vehicle M₀Length of car body, d_M0Is the vehicle M₀The width of the vehicle body; beta is the vehicle M₀In the lane changing process, the included angle between the connecting line of the geometric center of the vehicle and the circle center of the turning circle and the X axis can be determined according to the vehicle M at any time t₀Is calculated.

At this time, the geometric center point (X) of the vehicle_M0,Y_M0) The determination method of (2) is as follows:

first, the host vehicle M is calculated₀The angle theta corresponding to the arc track running on the lane in the turning process and the total length S of the lane changing arc are as follows:

S＝2R*θ；

where R is the selected turn radius and D is the lane width.

When the vehicle M₀When travelling at a constant speed (acceleration of travelling)Degree of 0):

step A1, calculating the vehicle M according to the total length S of the lane-changing arc₀At a constant speed V_M0And (4) performing lane change, and completing the time Tu required by lane change.

Step B1, whenThen, the vehicle M is calculated according to the following formula₀Coordinate (X) of the geometric center point of (2)_M0,Y_M0)。

It is obvious thatHour, the vehicle M₀The geometric center point of (2) is located on the lane:

step C1, whenThen, the vehicle M is calculated according to the following formula₀The coordinates of the geometric center point of (a).

It is obvious thatHour, the vehicle M₀Is located in the left lane, then:

wherein the vehicle M₀The most prominent part at the front left is the front left light, and the most prominent part at the back left is the back left light.

Then, at any time t (preferably, at the time of the vehicle M) when the vehicle travels₀Time node of entering the target lane), it is determined whether there is an executable turning radius R satisfying a preset condition (i.e., whether there is an executable lane-change path) among all preset, selectable turning radii, if there is an R value satisfying the preset condition, the R value is set as the target turning radius to the left lane, if there are a plurality of R values satisfying the preset condition, the largest one of the R values is selected as the turning radius to the left lane, otherwise it is determined that the vehicle has a collision risk, and the process proceeds to step S42.

When the vehicle M₀When driving at an acceleration a (driving acceleration greater than 0):

step A2, calculating the initial velocity V_M0Completing arc length of lane-changing path under acceleration aRequired time T_a1And the time T required for accelerating the completion of the arc length S of the lane-changing path_a2。

Host vehicle M₀The instantaneous speed at the geometric center lane boundary of (a) is V_B：

Step B2, when T is epsilon (0, T)_a1) Then, the vehicle M is calculated according to the following formula₀Coordinates of the geometric center point of (a):

obviously, when T ∈ (0, T)_a1) Hour, the vehicle M₀Is located in the lane, then:

step C2, when T is epsilon [ T ∈ [ ]_a1,T_a2]Then, the vehicle M is calculated according to the following formula₀Coordinates of the geometric center point of (a):

obviously, when T ∈ [ T ]_a1,T_a2]Hour, the vehicle M₀Is located in the left lane, then:

finally, at any time t (preferably, at the time of the vehicle M) when the vehicle is traveling₀Time node of entering the target lane), judging whether an executable turning radius R meeting preset conditions exists in all preset and selectable turning radii (namely whether an executable lane-changing path exists), if so, taking the R value as the target turning radius to change lanes to the left lane, if a plurality of R values meeting the preset conditions exist, selecting the maximum R value as the turning radius to change lanes to the left lane, otherwise, not performing lane-changing operation, implementing deceleration, performing the next round of calculation or terminating lane-changing calculation according to navigation or other conditions.

The acceleration a may be a fixed value, or may be stepped by Δ a with a (0) as an initial value and a (max) as an end value.

Similarly, if the vehicle is in the process of avoiding obstacles, the vehicle M₀The right lane exists on the right side, and the vehicle M on the right lane can be predicted at the same time of the left lane_RNVehicle M_RP1And vehicle M_RP2And carrying out obstacle avoidance calculation and judging whether lane changing is carried out on a lane preset path to the right. And if the conditions for changing the lane to the left and the right are both satisfied, controlling the vehicle to preferentially execute the lane change to the left according to the target turning radius R.

According to the method, according to the actual lane changing situation of the vehicle, path prediction covering the lane changing situation of a constant speed lane changing (the acceleration is 0) and an accelerated lane changing (the acceleration is greater than 0) is designed, preset conditions are preset to screen executable lane changing paths, then an optimal target lane changing path is selected according to preset rules, and the lane changing execution effect of the vehicle is further optimized.

The embodiment of the invention judges the vehicle M₀When lane changing is needed, the surrounding driving environment data are acquired and recognized, when a lane changing path is planned, the movement area of the target barrier in the lane changing judgment interval is acquired through the driving environment data, and whether the movement area is similar to the vehicle M in the expected lane changing path or not is calculated according to preset conditions₀The overlapping (collision) occurs, so that whether lane change can be implemented or not is determined, the calculation of the motion area and the lane change path is simple, but the dynamic obstacles on each lane can be effectively identified, and the driving safety is ensured.

Example 2

Reference numerals appearing in the drawings of the present embodiment include: the system comprises a perception module 1, an identification module 2, a path calculation module 3, a navigation module 4, a risk judgment module 5, a driving control module 6 and a database 7.

The embodiment of the invention also provides a lane changing and obstacle avoiding system based on automatic driving, which is shown in fig. 3 and comprises a sensing module 1, an identification module 2, a path calculation module 3, a navigation module 4, a risk judgment module 5, a driving control module 6 and a database 7;

the sensing module 1 is used for acquiring driving environment data;

in this embodiment, the sensing system includes sensing elements such as radar, image capture components (e.g., cameras or camcorders);

the identification module 2 is used for identifying driving environment data and determining the surrounding road condition and the vehicle data of a target vehicle;

the database 7 is used for storing vehicle characteristic data;

the path calculation module 3 is used for calculating the motion area of the target vehicle at any moment according to the vehicle data and the vehicle characteristic data;

the navigation module 4 is used for planning a lane change path according to the road condition;

a risk judgment module 5 for judging the vehicle M according to the preset conditions, the lane change path and the motion area₀Whether collision risks exist in lane changing or not is judged, and whether a lane changing path is executed or not is judged according to a judgment result;

and the driving control module 6 is used for receiving the control instruction of the risk judgment module 5 and executing the lane changing path or forbidding lane changing operation.

The travel control module 6 includes an oil/electric system, a brake system, and a steering system.

The road condition comprises traffic marks, and the traffic marks comprise lane lines, traffic marks and traffic signal lamps;

the vehicle characteristic data comprises wind resistance of the vehicle under different speed modes, wheel resistance under different load and road surface conditions, and corresponding relation between accelerator opening and speed change ratio and power output.

This embodiment adopts simple radar and image acquisition subassembly, and the perception system of group construction acquires driving environment data, low cost, and the computational efficiency of collision risk is high.

The lane changing and obstacle avoiding system provided by the embodiment adopts various modules to realize various steps of the lane changing and obstacle avoiding method in the embodiment 1, provides a hardware basis for the lane changing and obstacle avoiding method, and is convenient to implement.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.