Risk coefficient evaluation method and device for rear vehicle

Abstract

The present application relates to the field of intelligent vehicles, and provides a method and device for evaluating the risk coefficient of a vehicle behind. The method includes: obtaining the driving trajectory of the host vehicle in its own lane; determining the center line of the own lane and the center line of the adjacent lane based on the driving trajectory of the own lane; determining the area behind the host vehicle and the vehicle behind; when the host vehicle is in the lane keeping state, evaluating the risk coefficient of the vehicle behind affecting the host vehicle to achieve the assisted driving function according to the current lateral distance between the vehicle behind and the center line of the own lane, and the current lateral distance between the vehicle behind and the center line of the adjacent lane. The present application can improve the accuracy of the position and risk assessment of the vehicle behind, which is beneficial to reducing the probability of the host vehicle having overtaking and lane-changing logic errors or performing dangerous overtaking and lane-changing operations with a high risk coefficient when overtaking or changing lanes is required, thereby improving driving safety.

Description

Technical Field

[0001] This application relates to the field of intelligent vehicles, and particularly to a method and device for evaluating the risk coefficient of a vehicle behind. Background Art

[0002] In the field of transportation, when a vehicle is driving, overtaking and lane-changing driving behaviors often occur.

[0003] Before and after the overtaking and lane-changing processes, the accuracy of the self-vehicle's assessment of the position and risk of the vehicle behind it is crucial for realizing the assisted driving function and ensuring driving safety. If the self-vehicle's assessment of the position and risk of the vehicle behind is inaccurate, it may lead to incorrect overtaking and lane-changing logics or situations where the risk coefficient is high but dangerous overtaking and lane-changing still occur.

[0004] Therefore, how to improve the accuracy of the self-vehicle's assessment of the position and risk of the vehicle behind is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, embodiments of this application provide a method and device for evaluating the risk coefficient of a vehicle behind to solve the problem of how to improve the accuracy of the self-vehicle's assessment of the position and risk of the vehicle behind.

[0006] In the first aspect of the embodiments of this application, a method for evaluating the risk coefficient of a vehicle behind is provided, including:

[0007] Obtaining the driving trajectory of the vehicle in its own lane;

[0008] Based on the driving trajectory of the vehicle in its own lane, determining the center line of the own lane and the center line of the adjacent lane;

[0009] Determining the area of the vehicle behind and the vehicle behind. The vehicle behind is located within the area of the vehicle behind, and the area of the vehicle behind is located behind the backward dividing line of the parallel area of the vehicle. The backward dividing line of the parallel area is obtained by extending a preset backward distance along the driving direction of the vehicle with the center of the rear axle of the vehicle as the coordinate origin;

[0010] When the vehicle is in the lane-keeping state, evaluating the risk coefficient of the vehicle behind affecting the self-vehicle's realization of the assisted driving function according to the current lateral distance between the vehicle behind and the center line of the own lane and the current lateral distance between the vehicle behind and the center line of the adjacent lane.

[0011] In the second aspect of the embodiments of this application, a device for evaluating the risk coefficient of a vehicle behind is provided, including:

[0012] An obtaining module configured to obtain the driving trajectory of the vehicle in its own lane;

[0013] The first determination module is configured to determine the center line of the own lane and the center line of the adjacent lane based on the driving trajectory of the own lane;

[0014] The second determination module is configured to determine the rear vehicle area and the rear vehicle. The rear vehicle is located within the rear vehicle area, and the rear vehicle area is located behind the rearward dividing line of the parallel area of the own vehicle. The rearward dividing line of the parallel area is obtained by taking the center of the rear axle of the own vehicle as the coordinate origin and extending backward a preset rearward distance along the driving direction of the own vehicle;

[0015] The evaluation module is configured to, when the own vehicle is in the lane keeping state, evaluate the risk coefficient of the rear vehicle affecting the realization of the assisted driving function of the own vehicle according to the current own-rear lateral distance from the rear vehicle to the center line of the own lane and the current adjacent-rear lateral distance from the rear vehicle to the center line of the adjacent lane.

[0016] In the third aspect of the embodiments of the present application, there is provided an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0017] In the fourth aspect of the embodiments of the present application, there is provided a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0018] Compared with the prior art, the beneficial effects of the embodiments of the present application at least include: The center line of the own lane and the center line of the adjacent lane can be determined based on the driving trajectory of the own lane when the own vehicle is driving in the own lane, without the need to additionally install other hardware, with low cost, and the center line of the own lane and the center line of the adjacent lane can be updated in a timely manner following the change of the real-time position of the own vehicle, which is beneficial to improving the accuracy of evaluating the risk coefficient of the rear vehicle affecting the realization of the assisted driving function of the own vehicle; When the own vehicle is in the lane keeping state, the risk of the rear vehicle affecting the realization of the assisted driving function of the own vehicle is quantified according to the current own-rear lateral distance from the rear vehicle to the center line of the own lane and the current adjacent-rear lateral distance from the rear vehicle to the center line of the adjacent lane. The quantification rule is simple, the real-time performance of the system is good, and the accuracy of the position and risk assessment of the rear vehicle is relatively high, which is beneficial to reducing the probability of situations where the own vehicle has overtaking and lane-changing logic errors or a large risk coefficient but still performs dangerous overtaking and lane-changing when overtaking or lane-changing is required, thereby improving driving safety. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for use in the embodiments or the description of the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] Figure 1 It is a schematic flow chart of a method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0021] Figure 2 It is a schematic diagram of a way to record the driving trajectory points of the own lane on three lanes in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0022] Figure 3 It is a schematic diagram of a rear vehicle in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0023] Figure 4 It is another schematic diagram of a rear vehicle in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0024] Figure 5 It is a schematic diagram of a current vehicle coordinate system in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0025] Figure 6 It is a schematic diagram of the lateral distance between a rear vehicle and the center lines of three lanes in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0026] Figure 7 It is another schematic diagram of the lateral distance between a rear vehicle and the center lines of three lanes in the method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0027] Figure 8 It is a schematic structural diagram of a device for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application;

[0028] Figure 9 It is a schematic structural diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0029] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0030] A method and device for evaluating the risk coefficient of a rear vehicle according to an embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0031] Current assisted driving systems generally come with functions such as ACC (Adaptive Cruise Control), LCC (Lane Centering Control, lane centering assist system or lane keeping assist system), and NOA (Navigate on Autopilot). Moreover, LCC generally supports the function of changing lanes by operating the turn signal lever, and NOA can achieve functions such as autonomous overtaking and lane changing.

[0032] Before and after the overtaking and lane-changing processes, the accuracy of the self-vehicle's assessment of the position and risk of its rear vehicle is crucial for realizing the assisted driving function and ensuring driving safety. If the self-vehicle's assessment of the position and risk of the rear vehicle is inaccurate, it may lead to incorrect overtaking and lane-changing logic or the situation of performing dangerous overtaking and lane-changing despite a high risk coefficient.

[0033] In view of this, a method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application can determine the center line of the own lane (or the center line of the self-lane) and the center line of the adjacent lane based on the driving trajectory of the own vehicle (or the self-vehicle) in the own lane, without the need to install additional hardware, with low cost, and enabling the center line of the own lane and the center line of the adjacent lane to be updated in a timely manner following the change of the real-time position of the own vehicle, which is beneficial to improving the accuracy of evaluating the risk coefficient of the rear vehicle affecting the realization of the assisted driving function by the own vehicle; when the own vehicle is in the lane keeping state, the risk of the rear vehicle affecting the realization of the assisted driving function by the own vehicle is quantified according to the current lateral distance between the rear vehicle and the center line of the own lane and the current lateral distance between the rear vehicle and the center line of the adjacent lane. The quantification rule is simple, the real-time performance of the system is good, and the accuracy of the assessment of the position and risk of the rear vehicle is relatively high, which is beneficial to reducing the probability of incorrect overtaking and lane-changing logic or the situation of performing dangerous overtaking and lane-changing despite a high risk coefficient when the own vehicle needs to overtake or change lanes, thereby improving driving safety.

[0034] Figure 1It is a schematic flow chart of a method for evaluating the risk coefficient of a rear vehicle provided by an embodiment of the present application. The method for evaluating the risk coefficient of the rear vehicle can be executed by a vehicle controller of a vehicle (such as a new energy vehicle, etc.).

[0035] Please refer to Figure 1 , the method for evaluating the risk coefficient of the rear vehicle may include the following steps:

[0036] Step S101, obtain the driving trajectory of the vehicle in its own lane.

[0037] If the vehicle triggers an update of the driving trajectory in its own lane at the current moment, then the driving trajectory in its own lane includes 1 current driving trajectory point of the vehicle collected at the current moment and N - 1 historical driving trajectory points of the vehicle collected at N - 1 historical moments before the current moment; if the vehicle does not trigger an update of the driving trajectory in its own lane at the current moment, then the driving trajectory in its own lane includes N historical driving trajectory points of the vehicle collected at N moments before the current moment.

[0038] As an example, assume N = 10. If the vehicle triggers an update of the driving trajectory in its own lane at the current moment, then the driving trajectory in its own lane includes 1 current driving trajectory point of the vehicle collected at the current moment and 9 historical driving trajectory points of the vehicle collected at 9 historical moments before the current moment; if the vehicle does not trigger an update of the driving trajectory in its own lane at the current moment, then the driving trajectory in its own lane includes 10 historical driving trajectory points of the vehicle collected at the 10 historical moments before the current moment.

[0039] Since the rear lane of the vehicle cannot be directly sensed, the vehicle-mounted positioning sensor on the vehicle (such as a Global Positioning System (GPS) sensor, a BeiDou Navigation Satellite System (BDS) sensor, etc.) can be used to collect and record the driving trajectory points of the vehicle on its own lane during driving. Exemplarily, when the vehicle travels 5 meters each time, it triggers the vehicle-mounted positioning sensor on the vehicle to collect and record the driving trajectory points of the vehicle on its own lane (vehicle position information), and stores the collected driving trajectory points in a data container. Generally, the recording length of the data container is 50 meters, that is, a total of 10 driving trajectory points of the vehicle in its own lane are recorded and stored in the data container.

[0040] If the update of the driving trajectory of the current lane is triggered at the current moment, the earliest recorded historical driving trajectory point of the current lane in the data container can be deleted first, and the other historical driving trajectory points in the data container can be moved forward by one position. Then, the latest acquired current driving trajectory point of the current lane (i.e., the current position) is filled into the last position of the data container to obtain the updated driving trajectory of the current lane. For example, if the driving trajectory of the current lane recorded in the current data container includes 10 driving trajectory points of the current lane, namely dot1, dot2, dot3,..., dot10, and the update of the driving trajectory of the current lane is triggered at the current moment, then the earliest recorded historical driving trajectory point dot1 can be deleted first, and the other historical driving trajectory points in the data container (dot2, dot3,..., dot10) can be moved forward by one position, and the latest acquired current driving trajectory point dot11 of the current lane is stored in the last position of the data container. The updated driving trajectory of the current lane includes 10 driving trajectory points of the current lane, namely dot2, dot3,..., dot10, dot11.

[0041] Through the above method, the driving trajectory of the current lane recorded during the driving of the vehicle can be continuously updated, so that the driving trajectory of the current lane can be updated in a timely manner following the change of the real-time position of the vehicle.

[0042] Step S102: Determine the center line of the current lane and the center lines of adjacent lanes based on the historical driving trajectory and the current position.

[0043] As an example, please refer to Figure 2 , the vehicle can use the driving trajectory of the current lane stored in the data container to determine the center line of the current lane corresponding to the current driving lane of the vehicle. The center line of the current lane is the longitudinal central axis of the current lane, and the longitudinal central axis includes each driving trajectory point of the driving trajectory of the current lane when the vehicle is driving on the current lane.

[0044] For the lane-changing driving scenario, the cases of three lanes or two lanes are usually considered. If it is a three-lane case, the adjacent lanes of the current lane include the left lane and the right lane; if it is a two-lane case, the adjacent lane of the current lane includes either the left lane or the right lane. Taking the three-lane case as an example, the vehicle can determine the lane width through on-vehicle sensing sensors (such as on-vehicle cameras), and then, with the center point of the rear axle of the vehicle itself as the origin (point O), extend 1 times the lane width in both the left and right directions perpendicular to the current lane to determine point A and point B. Among them, point A is on the longitudinal center line of the left lane, and point B is on the longitudinal center line of the right lane. Then, record the adjacent-lane driving trajectory points on the adjacent lanes in the same way as the vehicle records its own driving trajectory points on the current lane. The adjacent-lane driving trajectory points include the left-lane driving trajectory points on the longitudinal center line of the left lane on the left side of the current lane, and the right-lane driving trajectory points on the longitudinal center line of the right lane on the right side of the current lane.

[0045] It can be understood that when the vehicle records each of its own driving trajectory points on the current lane, correspondingly, it will record point A (on the longitudinal center line of the left lane) and point B (on the longitudinal center line of the right lane) corresponding to this driving trajectory point on the current lane.

[0046] In the above way, by collecting and recording the driving trajectory points (point O) of the vehicle itself on the current lane, as well as the left-lane driving trajectory points (point A) and the right-lane driving trajectory points (point B) corresponding to this driving trajectory point (point O) on the current lane, the center line of the current lane and the center lines of the adjacent lanes can be determined without the need to additionally install other hardware, with low cost, and the center lines of the current lane and the adjacent lanes can follow the real-time position of the vehicle, which is beneficial to improving the accuracy of evaluating the risk coefficient of the rear vehicle for the vehicle to achieve the assisted driving function.

[0047] Step S103, determine the rear vehicle area and the rear vehicle. The rear vehicle is located within the rear vehicle area, and the rear vehicle area is located behind the rearward dividing line of the parallel area of the vehicle. The rearward dividing line of the parallel area is obtained by extending a preset rearward distance along the driving direction of the vehicle with the center of the rear axle of the vehicle as the coordinate origin.

[0048] As an example, please refer to Figure 3 , taking the center of the rear axle of the vehicle itself (such as the ego shown in Figure 3 ) as the coordinate origin (point O), extend a preset forward distance along the driving direction of the vehicle to obtain the forward dividing line of the parallel area, and extend a preset rearward distance along the driving direction of the vehicle to obtain the rearward dividing line of the parallel area. The lane area behind the rearward dividing line of the parallel area is the rear vehicle area.

[0049] Both the preset front distance and the preset rear distance can be flexibly set according to the actual situation. For example, the preset front distance can be set to 2 meters, and the preset rear distance can be set to 2.5 meters, etc. The present application does not make specific restrictions on this.

[0050] Among the rear vehicle areas (rear lane areas) of the vehicles in the current lane and adjacent lanes (including the left lane and the right lane), the vehicle with the shortest distance between the center of the front of the vehicle and the extension line of the rear axle center of the vehicle in the left-right direction is determined as the rear vehicle (such as Figure 3 the rear shown).

[0051] The vehicle can detect the distance between the center of the front of the vehicle in its rear vehicle area and the extension line of the rear axle center of the vehicle in the left-right direction through its on-vehicle sensors (such as environmental perception sensors (including cameras, lidar, etc.), vehicle state sensors (including vehicle speed sensors, etc.)).

[0052] Since the distance of the rear-rear vehicle (such as Figure 3 the rear-rear shown) from the vehicle is relatively far, it has little impact on the vehicle to implement the assisted driving function. Therefore, the rear-rear vehicle is generally not considered when implementing the technical solution of the present application.

[0053] As another example, please refer to Figure 4 , if the rear vehicle in the right lane (such as Figure 4 the rear in the right lane shown) is changing lanes, then it can be considered that the rear vehicle belongs to both the rear vehicle in the current lane and the rear vehicle in the right lane.

[0054] Step S104, when the vehicle is in the lane keeping state, evaluate the risk coefficient of the rear vehicle affecting the vehicle to implement the assisted driving function according to the current lateral distance between the rear vehicle and the center line of the current lane, and the current lateral distance between the rear vehicle and the center line of the adjacent lane.

[0055] The current lateral distance between the rear vehicle and the center line of the current lane refers to the lateral distance between the rear axle center of the rear vehicle at the current moment and the center line of the current lane.

[0056] The current lateral distance between the rear vehicle and the center line of the adjacent lane refers to the lateral distance between the rear axle center of the rear vehicle at the current moment and the center line of the adjacent lane.

[0057] The technical solution provided by the embodiments of the present application can determine the center line of the current lane and the center line of the adjacent lane based on the driving trajectory of the vehicle in the current lane, without the need to install additional hardware, which has a lower cost. Moreover, it enables the center line of the current lane and the center line of the adjacent lane to change according to the real-time position of the vehicle, which is beneficial to improving the accuracy of evaluating the risk coefficient of the rear vehicle for the vehicle to achieve the assisted driving function. When the vehicle is in the lane keeping state, according to the current lateral distance between the rear vehicle and the center line of the current lane and the current lateral distance between the rear vehicle and the center line of the adjacent lane, the risk of the rear vehicle affecting the vehicle to achieve the assisted driving function is quantified. The quantification rule is simple, the real-time performance of the system is good, and the accuracy of the position and risk assessment of the rear vehicle is relatively high, which is beneficial to reducing the probability of the vehicle making overtaking and lane-changing logic errors or performing dangerous overtaking and lane-changing with a high risk coefficient when overtaking or changing lanes is required, thereby improving driving safety.

[0058] In some embodiments, based on the driving trajectory of the current lane, determining the center line of the current lane and the center line of the adjacent lane includes:

[0059] Establish a current vehicle coordinate system based on the current position of the vehicle, and update the relative positions of the driving trajectory points of the current lane in the current vehicle coordinate system;

[0060] Based on the relative positions, determine the center line of the current lane and the center line of the adjacent lane.

[0061] Please refer to Figure 5 , assuming that the current position of the vehicle at the current moment is located at the point, the vehicle body orientation is , the vehicle global coordinate is ( , ), taking the point as the coordinate origin, establish the current vehicle coordinate system ; the current yaw angle (yaw angle) of the vehicle is (which can be obtained through on-vehicle sensors). Assuming that at the previous moment, the vehicle was located at the point, the vehicle body orientation was , and the corresponding global coordinate was ( , ), and at this time the current yaw angle (yaw angle) of the vehicle was 0 degrees.

[0062] Exemplarily, the mathematical expression of the distance between the current position of the vehicle at the current moment and its vehicle position at the previous moment is shown in Equation (1):

[0063] (1);

[0064] In Equation (1), distanceIndicates the distance between the current position of the vehicle at the current moment and its vehicle position at the previous moment.

[0065] From Figure 5 Equations (2) to (4) can be derived as follows:

[0066] (2);

[0067] (3);

[0068] (4);

[0069] Then the position of the vehicle at the previous moment The relative position (Y0, X0) of the point in the current vehicle coordinate system can be calculated by Equations (5) to (6):

[0070] ; (5);

[0071] ; (6).

[0072] Similarly, the relative positions of the respective lane driving trajectory points on the lane driving trajectory of the vehicle on the current lane stored in the data container can be updated in the above manner. The relative positions of the respective adjacent lane driving trajectory points in the current vehicle coordinate system can also be updated in the above manner, which will not be elaborated here.

[0073] After updating the relative positions of the respective lane driving trajectory points on the lane driving trajectories of the current lane and the adjacent lanes in the current vehicle coordinate system, these relative positions are used for lane centerline fitting. For example, the least squares method can be used to fit the lane centerline equation in the form of a cubic polynomial (a fifth-degree polynomial can also be used).

[0074] Taking a three-lane scenario as an example, assume that the three lane centerline equations are fitted as shown in the following Equations (7) to (9):

[0075] (7);

[0076] (8);

[0077] (9);

[0078] Among them, Equation (7) is the equation of the centerline of the lane behind the left of the vehicle (left lane centerline), is the coefficient of this equation, represents the abscissa of the relative position of the left lane driving trajectory point in the current vehicle coordinate system, represents the ordinate of the relative position of the driving trajectory points in the left lane in the current vehicle coordinate system; Equation (8) is the equation of the center line of the lane behind the vehicle (the center line of this lane), is the coefficient of this equation, represents the abscissa of the relative position of the driving trajectory points in this lane in the current vehicle coordinate system, represents the ordinate of the relative position of the driving trajectory points in this lane in the current vehicle coordinate system; Equation (9) is the equation of the center line of the lane behind the vehicle on the right rear side of the vehicle (the center line of the right lane), is the coefficient of this equation, represents the abscissa of the relative position of the driving trajectory points in the right lane in the current vehicle coordinate system, represents the ordinate of the relative position of the driving trajectory points in the right lane in the current vehicle coordinate system.

[0079] According to Equations (10) to (12), the lateral distances from the center of the rear axle of the vehicle to the center lines of the three lanes (the center line of this lane, the center line of the left lane, and the center line of the right lane) in the current vehicle coordinate system can be calculated respectively:

[0080] (10);

[0081] (11);

[0082] (12);

[0083] In Equations (10) to (12), represents the lateral distance from the center of the rear axle of the vehicle to the center line of the left lane in the left lane in the current vehicle coordinate system; represents the difference between the ordinate of the relative position of the center of the rear axle of the vehicle in the current vehicle coordinate system and the ordinate of the point corresponding to the relative position of the center of the rear axle of the vehicle on the center line of the left lane; is the coefficient of the equation of the center line of the left lane; represents the lateral distance from the center of the rear axle of the vehicle to the center line of this lane in this lane in the current vehicle coordinate system; represents the difference between the ordinate of the relative position of the center of the rear axle of the vehicle in the current vehicle coordinate system and the ordinate of the point corresponding to the relative position of the center of the rear axle of the vehicle on the center line of this lane; is the coefficient of the equation of the center line of this lane; represents the lateral distance from the center of the rear axle of the vehicle to the center line of the right lane in the right lane in the current vehicle coordinate system; represents the difference between the ordinate of the relative position of the center of the rear axle of the vehicle in the current vehicle coordinate system and the ordinate of the point corresponding to the relative position of the center of the rear axle of the vehicle on the center line of the right lane; are the coefficients of the equation of the center line of the right lane.

[0084] In some embodiments, according to the current lateral distance between the vehicle behind and the center line of this lane, and the current lateral distance between the vehicle behind and the center line of the adjacent lane, the risk coefficient of the vehicle behind affecting the vehicle to achieve the assisted driving function is evaluated, including:

[0085] If the vehicle behind is the vehicle behind in this lane, then according to the current lateral distance between the vehicle behind in this lane and the center line of this lane, and the current lateral distance between the vehicle behind in this lane and the center line of the adjacent lane, determine the current driving state of the vehicle behind in this lane;

[0086] If the current driving state is the lane keeping state, then determine at least one of the first imminent collision time, the first time-to-distance, or the first longitudinal safety distance between the vehicle behind in this lane and the vehicle;

[0087] Based on at least one of the first imminent collision time, the first time-to-distance, or the first longitudinal safety distance, determine the first risk coefficient of the vehicle behind in this lane affecting the vehicle to achieve the assisted driving function.

[0088] The first imminent collision time is mainly used to judge the time relationship between the vehicle behind in this lane and the vehicle. Specifically, the first imminent collision time is calculated by dividing the distance between the vehicle behind in this lane and the vehicle by the relative speed. By calculating the first imminent collision time between the vehicle behind in this lane and the vehicle, it helps to predict when the vehicle behind in this lane and the vehicle will collide. Generally speaking, the shorter the first imminent collision time, the closer the distance between the vehicle behind in this lane and the vehicle, and the greater the relative speed, then the risk of the vehicle behind in this lane affecting the vehicle to achieve the assisted driving function is relatively greater.

[0089] The first time-to-distance is the result obtained by dividing the distance between the vehicle behind in this lane and the vehicle by the speed of the vehicle behind in this lane, that is, without considering the vehicle speed of the vehicle, only considering the vehicle speed of the vehicle behind in this lane. The first time-to-distance mainly reflects the safety distance and safety time to maintain safety between the vehicle behind in this lane and the vehicle, but this value has different meanings in different traffic environments and speeds. For example, on the highway, due to the relatively high vehicle speed, a longer first time-to-distance is required to ensure safety; while in urban streets or low-speed areas, a shorter first time-to-distance may be acceptable.

[0090] The first longitudinal safety distance refers to the distance that can avoid collisions even in the worst-case scenario. Here, the "worst-case scenario" means that the vehicle brakes with the maximum deceleration, and the vehicle behind in the same lane has a certain reaction time after discovery and continues to move forward with the maximum acceleration during the reaction time, and then changes to brake with the minimum deceleration. If collisions can be avoided under such circumstances, then there is no possibility of rear-ending the vehicle in front for the autonomous vehicle.

[0091] Please refer to Figure 3 , the vehicle behind in the same lane refers to the vehicle with the closest distance between the center line of the vehicle head and the extension line of the center of the rear axle of the vehicle in the left-right direction within the area of the vehicle behind in the same lane.

[0092] The current lateral distance between the front and the rear refers to the lateral distance between the center line of the longitudinal axis of the vehicle behind (such as the vehicle behind in the same lane) at the current moment (or the center of the rear axle of the vehicle) and the center line of the same lane. Among them, the center line of the longitudinal axis of the vehicle is an imaginary straight line that passes through the midpoint of the front end of the vehicle and the midpoint of the rear end when the vehicle is parked horizontally, bisecting the vehicle into two completely symmetrical left and right parts along the length direction, and it is consistent with the forward direction of the vehicle's travel.

[0093] The current lateral distance between the adjacent vehicle behind refers to the lateral distance between the center of the rear axle of the vehicle behind (such as the vehicle behind in the same lane) at the current moment and the center line of the adjacent lane.

[0094] Please refer to Figure 6 , taking a three-lane road as an example, the center lines of the adjacent lanes include the center line of the left lane and the center line of the right lane. The current lateral distance between the adjacent vehicle behind includes the current lateral distance between the left vehicle behind and the current lateral distance between the right vehicle behind. The current lateral distance between the left vehicle behind represents the lateral distance between the center of the rear axle of the vehicle behind (such as the vehicle behind in the same lane) and the center line of the left lane. The current lateral distance between the right vehicle behind represents the lateral distance between the center of the rear axle of the vehicle behind (such as the vehicle behind in the same lane) and the center line of the right lane.

[0095] Exemplarily, the lateral distance between the center of the rear axle of the vehicle behind located in the area of the vehicle behind of the vehicle itself can be detected by the in-vehicle sensors of the vehicle itself. Then, according to Equations (13) - (15), the lateral distances between the center of the rear axle of the vehicle behind located in the area of the vehicle behind of the vehicle itself and the center line of the same lane, the center line of the left lane, and the center line of the right lane are calculated respectively.

[0096] (13);

[0097] (14);

[0098] (15);

[0099] In Formulas (13) to (15), represents the lateral distance from the center of the rear axle of the vehicle behind (the target vehicle) to the center line of the left lane of the left lane, that is, the current left-rear lateral distance; represents the lateral distance from the center of the rear axle of the vehicle behind (the target vehicle) to the center line of this lane of this lane, that is, the current own-rear lateral distance; represents the lateral distance from the center of the rear axle of the vehicle behind (the target vehicle) to the center line of the right lane of the right lane, that is, the current right-rear lateral distance; represents the lateral distance between the center of the rear axle of the vehicle behind (the target vehicle) and the center of the rear axle of this vehicle; abs() represents the absolute value function; represents the lateral distance from the center of the rear axle of this vehicle to the center line of the left lane of the left lane, which can be calculated according to the above Formula (10); represents the lateral distance from the center of the rear axle of this vehicle to the center line of this lane of this lane, which can be calculated according to the above Formula (11); represents the lateral distance from the center of the rear axle of this vehicle to the center line of the right lane of the right lane, which can be calculated according to the above Formula (12).

[0100] As an example, please refer to Figure 6 to establish an xoy coordinate system with the current position o point of this vehicle. Assume that the lateral distance in the direction same as the y axis direction takes a positive value, and the lateral distance in the direction opposite to the y axis direction takes a negative value. Then is a positive value, is a positive value, is a negative value.

[0101] In some embodiments, according to the current own-rear lateral distance of the vehicle behind in this lane to the center line of this lane, and the current adjacent-rear lateral distance of the vehicle behind in this lane to the center line of the adjacent lane, determine the current driving state of the vehicle behind in this lane, including:

[0102] Calculate the current own-rear percentage between the current own-rear lateral distance and the standard lane half-width, and calculate the current adjacent-rear percentage between the current adjacent-rear lateral distance and the standard lane half-width;

[0103] According to the current own-rear percentage and the current adjacent-rear percentage, determine the current driving state of the vehicle behind in this lane.

[0104] Exemplarily, the current own-rear percentage between the current own-rear lateral distance and the standard lane half-width can be calculated according to Formula (16) ProbInEgo .

[0105] ProbInEgo= (16);

[0106] In formula (16), ProbInEgo represents the current percentage of the current rear lateral distance to the standard lane half-width; represents the current rear lateral distance from the rear vehicle (such as the vehicle behind in this lane) to the center line of this lane; represents the standard lane half-width; represents the standard lane width, generally 3.75 meters, so the standard lane half-width is 1.875 meters.

[0107] As an example, the adjacent lane center line includes the left lane center line and the right lane center line; the current adjacent rear lateral distance includes the current left rear lateral distance and the current right rear lateral distance. The current left rear lateral distance represents the lateral distance from the vehicle behind in this lane to the left lane center line, and the current right rear lateral distance represents the lateral distance from the vehicle behind in this lane to the right lane center line; the current adjacent rear percentage includes the current left rear percentage and the current right rear percentage.

[0108] The current left rear percentage between the current left rear lateral distance and the standard lane half-width can be calculated according to formula (17); the current right rear percentage between the current right rear lateral distance and the standard lane half-width can be calculated according to formula (18).

[0109] ProbInLeft= (17);

[0110] In formula (17), ProbInLeft represents the current left rear percentage between the current left rear lateral distance and the standard lane half-width; represents the current left rear lateral distance.

[0111] ProbInRight= (18);

[0112] In formula (18), ProbInRight represents the current right rear percentage between the current right rear lateral distance and the standard lane half-width, represents the current right rear lateral distance.

[0113] When the rear vehicle is in a certain lane, its lateral distance to the center line of that lane is less than or equal to half of the lane width (i.e., the standard lane half-width); by calculating the percentage between the lateral distance from the rear vehicle to the center line of each lane and half of the lane width, the larger this percentage, the farther the rear vehicle is from the center line of that lane.

[0114] For example, when the vehicle behind is in the same lane, it is the vehicle behind in this lane, and its lateral distance to the center line of this lane is less than or equal to half of the lane width (i.e., the standard lane half-width). When the current percentage between the current lateral distance from the vehicle behind in this lane to the center line of this lane and the standard lane half-width is larger, it indicates that the vehicle behind in this lane is farther from the center line of this lane. On the contrary, the smaller the current percentage, the closer the vehicle behind in this lane is to the center line of this lane.

[0115] In some cases, refer to Figure 4 , when the vehicle behind presses on the shared boundary line between this lane and the right lane, then the current percentage between the current lateral distance from the center of the rear axle of the vehicle behind to the center line of this lane and the standard lane half-width, and the current percentage between the current lateral distance from the center of the rear axle of the vehicle behind to the center line of the right lane and the standard lane half-width may both be close to 1, which poses a certain risk to safety judgment. At this time, considering the safety of the vehicle changing lanes, the vehicle behind is assigned to the right lane, and the vehicle behind can be classified as the vehicle behind in the right lane. After that, when calculating the current left-rear percentage and the current right-rear percentage of the vehicle behind in the right lane, an offset term ( offset ) needs to be added based on the standard lane half-width to reduce the current left-rear percentage and the current right-rear percentage. Among them, the specific value of the offset term can be calibrated on the actual vehicle according to the actual situation, and generally can be set to 0.1 - 0.2.

[0116] Exemplarily, the current left-rear percentage of the vehicle behind can be calculated according to Equation (19); the current right-rear percentage of the vehicle behind can be calculated according to Equation (20).

[0117] ProbInLeft' = (19);

[0118] In Equation (19), ProbInLeft' represents the current left-rear percentage considering the vehicle behind pressing on the boundary line of one side lane; offset represents the offset term; represents the current left-rear lateral distance; represents the standard lane half-width.

[0119] ProbInRight' = (20);

[0120] In Equation (20), ProbInRight' represents the current right-rear percentage considering the vehicle behind pressing on the boundary line of one side lane; t represents the offset term; represents the current right-rear lateral distance; Represents the half-width of the standard lane.

[0121] In some embodiments, according to the current following percentage of the own lane and the current following percentage of the adjacent lane, determine the current driving state of the vehicle behind in the own lane, including:

[0122] If the current following percentage of the own lane is less than 1 and remains less than 1 within the first duration, and the current left following percentage and the current right following percentage are greater than 1 and remain greater than 1 within the first duration, then determine that the current driving state of the vehicle behind in the own lane is the lane-keeping state;

[0123] If the current following percentage of the own lane is greater than 1 and the current following percentage of the own lane is greater than the historical following percentage of the own lane in the Mth cycle before the current cycle, and the current left following percentage is less than the historical left following percentage of the Mth cycle before the current cycle, and the current right following percentage is greater than the historical right following percentage of the Mth cycle before the current cycle, then determine that the current driving state of the vehicle behind in the own lane is the left lane-changing driving state;

[0124] If the current following percentage of the own lane is greater than 1, and the current following percentage of the own lane is greater than the historical following percentage of the own lane in the Mth cycle before the current cycle, and the current left following percentage is greater than the historical left following percentage of the Mth cycle before the current cycle, and the current right following percentage is less than the historical right following percentage of the Mth cycle before the current cycle, then determine that the current driving state of the vehicle behind in the own lane is the right lane-changing driving state, where M is a positive integer.

[0125] The first duration can be flexibly set according to the actual situation. Generally, it can be set to 3 seconds. If the execution frequency is 50Hz, that is, one cycle is 0.02 seconds, then 3 seconds includes 150 cycles.

[0126] As an example, assume that the vehicle behind is the vehicle behind in the own lane. If this vehicle behind in the own lane simultaneously meets the following conditions: ① The current following percentage of the vehicle behind in the own lane ProbInEgo <1, and within the first duration (such as within 3 seconds) ProbInEgo are all less than 1, that is, within 150 cycles ProbInEgo are all less than 1; ② The current left following percentage of the vehicle behind in the own lane ProbInLeft >1, the current right following percentage ProbInRight >1, and within the first duration (such as within 3 seconds) ProbInLeft 、 ProbInRight are all greater than 1. If the vehicle behind in the own lane simultaneously meets the above conditions ① and ②, then it can be determined that the current driving state of this vehicle behind in the own lane is the lane-keeping state.

[0127] As another example, assume that the vehicle behind is a vehicle behind in the same lane. If the vehicle behind in the same lane simultaneously meets the following conditions: ③ the current percentage of the vehicle behind in the same lane ProbInEgo > 1, and the current percentage of the vehicle behind in the same lane in the current cycle ProbInEgo is greater than the historical percentage of the vehicle behind in the same lane in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago); ④ the current percentage of the vehicle behind on the left in the same lane ProbInLeft is less than the historical percentage of the vehicle behind on the left in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago), and the current percentage of the vehicle behind on the right in the same lane ProbInRight is greater than the historical percentage of the vehicle behind on the right in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago). If the vehicle behind in the same lane simultaneously meets the above conditions ③ and ④, then it can be determined that the current driving state of the vehicle behind in the same lane is a left lane change driving state.

[0128] Among them, the calculation methods of the historical percentage of the vehicle behind in the same lane, the historical percentage of the vehicle behind on the left, and the historical percentage of the vehicle behind on the right can refer to the calculation methods of the current percentage of the vehicle behind in the same lane, the current percentage of the vehicle behind on the left, and the current percentage of the vehicle behind on the right, which will not be elaborated here.

[0129] As yet another example, assume that the vehicle behind is a vehicle behind in the same lane. If the vehicle behind in the same lane simultaneously meets the following conditions: ⑤ the current percentage of the vehicle behind in the same lane ProbInEgo > 1, and the current percentage of the vehicle behind in the same lane in the current cycle ProbInEgo is greater than the historical percentage of the vehicle behind in the same lane in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago); ⑥ the current percentage of the vehicle behind on the left in the same lane ProbInLeft is greater than the historical percentage of the vehicle behind on the left in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago), and the current percentage of the vehicle behind on the right in the same lane ProbInRight is less than the historical percentage of the vehicle behind on the right in the Mth (assuming M = 100) cycle before the current cycle (i.e., 2 seconds ago). If the vehicle behind in the same lane simultaneously meets the above conditions ⑤ and ⑥, then it can be determined that the current driving state of the vehicle behind in the same lane is a right lane change driving state.

[0130] In some embodiments, if the vehicle behind is a vehicle behind in the same lane and the current driving state of the vehicle behind in the same lane is a lane keeping state, then the first time to collision TTC1 between the vehicle behind in the same lane and the vehicle itself can be calculated according to Equation (21).

[0131] (21);

[0132] In Equation (21),TTC 1 represents the first impending collision time between the vehicle behind in this lane and the vehicle itself; represents the distance between the vehicle behind in this lane and the vehicle itself; represents the current driving speed of the vehicle behind in this lane; represents the current driving speed of the vehicle itself.

[0133] The current driving speed of the vehicle behind in this lane, the current driving speed of the vehicle itself, and the distance between the vehicle behind in this lane and the vehicle itself can be detected by the on-vehicle sensors of the vehicle itself.

[0134] The first distance-to-time of the vehicle behind in this lane and the vehicle itself can be calculated according to Equation (22) THW 1.

[0135] (22);

[0136] In Equation (22), represents the first distance-to-time of the vehicle behind in this lane and the vehicle itself; represents the distance between the vehicle behind in this lane and the vehicle itself; represents the current driving speed of the vehicle behind in this lane.

[0137] The first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself can be calculated according to Equation (23) .

[0138] (23);

[0139] In Equation (23), represents the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself; represents the current driving speed of the vehicle behind in this lane; represents the reaction time of the vehicle behind in this lane; represents the maximum acceleration of the vehicle behind in this lane during the reaction time; represents the minimum braking acceleration that the vehicle behind in this lane must implement after the reaction time; represents the maximum braking acceleration when the vehicle itself brakes; represents the current driving speed of the vehicle itself. The "+" after the formula means that the calculated needs to be compared with 0 and take the maximum value, that is max { , 0}.

[0140] If the vehicle behind is a vehicle behind in the same lane and the current driving state of the vehicle behind in the same lane is in the lane-keeping state, the first risk coefficient of the vehicle behind in the same lane affecting the vehicle's realization of the assisted driving function can be determined according to at least one of the first time-to-collision, the first time headway, or the first longitudinal safety distance between the vehicle behind in the same lane and the vehicle itself.

[0141] In the first case, the first risk coefficient of the vehicle behind in the same lane affecting the vehicle's realization of the assisted driving function can be determined according to the first time-to-collision between the vehicle behind in the same lane and the vehicle itself.

[0142] Exemplarily, the first risk coefficient can be calculated according to Equation (24).

[0143] (24);

[0144] In Equation (24), 1 represents the first risk coefficient of the vehicle behind in the same lane affecting the vehicle's realization of the assisted driving function; represents the first time-to-collision between the vehicle behind in the same lane and the vehicle itself; k 1 represents the first threshold for the vehicle itself to enter the risk area, and its value can be adjusted according to the road environment.

[0145] Next, according to the correspondence between the risk coefficient and the risk level, the risk level corresponding to the first risk coefficient can be determined. Generally, the larger the first time-to-collision, that is, the longer the time until the vehicle behind in the same lane and the vehicle itself are about to collide, the lower the risk, and the smaller the first risk coefficient.

[0146] Exemplarily, the correspondence between the risk coefficient and the risk level is as follows: when the risk coefficient is in [0, 0.3], the corresponding risk level is low risk; when the risk coefficient is in (0.3, 0.6], the corresponding risk level is medium risk; when the risk coefficient is in (0.6, 1], the corresponding risk level is high risk.

[0147] In the second case, the first risk coefficient of the vehicle behind in the same lane affecting the vehicle's realization of the assisted driving function can be determined according to the first time headway between the vehicle behind in the same lane and the vehicle itself.

[0148] Exemplarily, the first risk coefficient can be calculated according to Equation (25).

[0149] (25);

[0150] In Equation (25), 1 represents the first risk coefficient of the vehicle behind in the same lane affecting the vehicle's realization of the assisted driving function; Indicates the first time headway between the vehicle behind in this lane and the vehicle itself; k 2 represents the second threshold for the vehicle itself to enter the risk area, and its value can be adjusted according to the road environment.

[0151] Similarly, according to the correspondence between the risk coefficient and the risk level, the risk level corresponding to the first risk coefficient can be determined.

[0152] In the third case, the first risk coefficient of the vehicle behind in this lane affecting the vehicle itself to achieve the assisted driving function can be determined according to the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself.

[0153] Exemplarily, the first risk coefficient can be calculated according to Equation (26).

[0154] (26);

[0155] In Equation (26), 1 represents the first risk coefficient of the vehicle behind in this lane affecting the vehicle itself to achieve the assisted driving function; represents the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself; represents the actual distance between the vehicle behind in this lane and the vehicle itself.

[0156] If ≥2 , then the first risk coefficient is 0; if = , then the first risk coefficient is 1; if ＜ , it means that the vehicle itself enters the high-risk area, and the first risk coefficient is also 1.

[0157] In the fourth case, the first risk coefficient of the vehicle behind in this lane affecting the vehicle itself to achieve the assisted driving function can be determined according to the first time to collision and the first time headway between the vehicle behind in this lane and the vehicle itself.

[0158] The first risk coefficient of the vehicle behind in this lane affecting the vehicle itself to achieve the assisted driving function can be calculated respectively according to the above-mentioned Equation (24) and Equation (25), and then the first risk coefficients calculated by Equation (24) and Equation (25) are compared, and the maximum value among them is taken as the final first risk coefficient.

[0159] In the fifth case, the first risk coefficient of the vehicle behind in this lane affecting the vehicle itself to achieve the assisted driving function can be determined according to the first time to collision and the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself.

[0160] According to the above formulas (24) and (26), the first risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function can be calculated respectively, and then the first risk coefficients calculated by formulas (24) and (26) are compared, and the maximum value among them is taken as the final first risk coefficient.

[0161] In the sixth case, the first risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function can be determined according to the first time-to-distance and the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself.

[0162] According to the above formulas (25) and (26), the first risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function can be calculated respectively, and then the first risk coefficients calculated by formulas (25) and (26) are compared, and the maximum value among them is taken as the final first risk coefficient.

[0163] In the seventh case, the first risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function can be determined according to the first time-to-collision, the first time-to-distance and the first longitudinal safety distance between the vehicle behind in this lane and the vehicle itself.

[0164] According to the above formulas (24), (25) and (26), the first risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function can be calculated respectively, and then the first risk coefficients calculated by formulas (24), (25) and (26) are compared, and the maximum value among them is taken as the final first risk coefficient.

[0165] In some embodiments, if the vehicle behind is the vehicle behind in this lane, after determining the current driving state of the vehicle behind in this lane according to the current lateral distance from the vehicle behind in this lane to the center line of this lane and the current lateral distance from the vehicle behind in this lane to the center line of the adjacent lane, it further includes:

[0166] If the current driving state is a left lane change driving state, calculate the second time-to-collision between the vehicle behind in this lane and the vehicle itself, and the lateral displacement distance of the vehicle behind in this lane within the second time-to-collision;

[0167] Based on the lateral displacement distance, determine whether the vehicle behind in this lane can completely drive into the left lane within the second time-to-collision;

[0168] If so, determine the second risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function;

[0169] If not, based on the lateral displacement distance, determine the third risk coefficient of the vehicle behind in this lane affecting the vehicle's realization of the assisted driving function, and the third risk coefficient is greater than the second risk coefficient.

[0170] If the vehicle behind is a vehicle behind in the same lane and the current driving state is a left lane change driving state, then the second time to collision TTC2 between the vehicle behind in the same lane and the host vehicle can be calculated with reference to Equation (21) above.

[0171] Calculate the lateral displacement distance that the vehicle behind in the same lane can traverse within the second time to collision according to Equation (27).

[0172] (27);

[0173] In Equation (27), represents the lateral displacement distance that the vehicle behind in the same lane can traverse within the second time to collision; represents the lateral speed of the vehicle behind in the same lane; represents the second time to collision.

[0174] If ≥ , then it can be determined that the vehicle behind in the same lane can fully enter the left lane within the second time to collision. At this time, the risk coefficient of the vehicle behind in the same lane affecting the host vehicle's realization of the assisted driving function is significantly reduced. At this time, the second risk coefficient of the vehicle behind in the same lane affecting the host vehicle's realization of the assisted driving function 2 is reduced to close to 0. Generally, 2 takes values in the range of (0, 0.2).

[0175] If < , then it can be determined that the vehicle behind in the same lane cannot fully enter the left lane within the second time to collision. Assuming that the risk coefficient of the vehicle behind in the same lane affecting the host vehicle's realization of the assisted driving function decreases linearly with the increase of the lateral displacement distance, then the third risk coefficient of the vehicle behind in the same lane affecting the host vehicle's realization of the assisted driving function can be calculated according to Equation (28).

[0176] (28);

[0177] In Equation (28), represents the third risk coefficient of the vehicle behind in the same lane affecting the host vehicle's realization of the assisted driving function; represents the lateral displacement distance that the vehicle behind in the same lane can traverse within the second time to collision; represents the standard lane width.

[0178] Generally, when the lateral overlap degree between the vehicle behind in this lane and the host vehicle is lower, that is, the greater the lateral displacement distance that the vehicle behind in this lane can traverse within the second imminent collision time, it indicates that the more parts of the vehicle behind in this lane enter the left lane or the right lane. Then, the corresponding risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function is smaller, and the risk level is lower. When the lateral overlap degree between the vehicle behind in this lane and the host vehicle is higher, that is, the smaller the lateral displacement distance that the vehicle behind in this lane can traverse within the second imminent collision time, it indicates that the fewer parts of the vehicle behind in this lane enter the left lane or the right lane. Then, the corresponding risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function is larger, and the risk level is higher.

[0179] In the RSS model, the definition of the lateral safety distance is as follows: For cars c1 and c2 traveling at lateral speeds v1 and v2, if within the time interval [0, ρ , the two cars accelerate towards each other with the maximum lateral acceleration, and then the two cars will apply lateral braking to brake with the minimum lateral deceleration until the relative lateral speed between them is zero. If a collision can be avoided in this case, then it is safe for the autonomous vehicle.

[0180] In some embodiments, after the step of determining the third risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function based on the lateral displacement distance, it further includes:

[0181] Calculating the second longitudinal safety distance between the vehicle behind in this lane and the host vehicle, and determining the fourth risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function based on the second longitudinal safety distance;

[0182] Based on the third risk coefficient, the fourth risk coefficient, and a preset first offset term, determining the final risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function.

[0183] As an example, considering that the vehicle behind in this lane may accelerate and overtake after changing lanes, the second longitudinal safety distance between the vehicle behind in this lane and the host vehicle can be further determined according to the RSS (Responsibility Sensitive Safety) model . The second longitudinal safety distance between the vehicle behind in this lane and the host vehicle can be calculated with reference to the above formula (20) . The fourth risk coefficient of the vehicle behind in this lane affecting the host vehicle's realization of the assisted driving function is calculated with reference to the above formula (23) 4 .

[0184] Since the current driving state of the vehicle behind in this lane is a left lane change driving state and it is not completely located in this lane, when the vehicle behind in this lane cannot completely enter the left lane within the second imminent collision time, the final risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle can be determined according to Equation (29).

[0185] =min(1,max( -offset 1 ) (29);

[0186] In Equation (29), represents the final risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; represents the third risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; represents the fourth risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; offset 1 represents a preset first offset term, and its value is generally a value greater than 0, and its value range is generally 0.1 - 0.3. For example, it can be set to 0.2.

[0187] As another example, when the vehicle behind in this lane can completely enter the left lane within the second imminent collision time, the final risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle can be determined according to Equation (30).

[0188] =min(1,max( -offset 1 ) (30);

[0189] In Equation (30), represents the final risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; represents the second risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; represents the fourth risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; offse t1 represents a preset offset term, and its value is generally a value greater than 0, and its value range is generally 0.1 - 0.3. For example, it can be set to 0.2.

[0190] In some embodiments, if the vehicle behind is the vehicle behind in this lane and its current driving state is a right lane change driving state, then the risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle can be determined by referring to the above-mentioned situation where the vehicle behind in this lane is in a left lane change driving state, and details are not described herein again.

[0191] In some embodiments, according to the current lateral distance between the rear vehicle and the center line of this lane, and the current lateral distance between the rear vehicle and the center line of the adjacent lane, the risk coefficient of the rear vehicle affecting the vehicle to achieve the assisted driving function is evaluated, including:

[0192] If the rear vehicle is a rear vehicle in the adjacent lane and the current driving state of the rear vehicle in the adjacent lane is the lane keeping state, then calculate the third longitudinal safety distance between the rear vehicle in the adjacent lane and the vehicle.

[0193] Based on the third longitudinal safety distance and the preset second offset term, determine the fifth risk coefficient of the rear vehicle in the adjacent lane affecting the vehicle to achieve the assisted driving function.

[0194] Please refer to Figure 7 , taking the rear vehicle in the right lane as an example. The method for calculating the current rear percentage, the current left rear percentage, and the current right rear percentage of the rear vehicle in this lane in the above embodiments can be referred to calculate the current rear percentage of the rear vehicle in the right lane ProbInEgo_1 (representing the percentage of the lateral distance from the center of the rear axle of the rear vehicle in the right lane at the current moment to the center line of this lane and the standard lane half-width), the current left rear percentage ProbInLeft_1 (representing the percentage of the lateral distance from the center of the rear axle of the rear vehicle in the right lane at the current moment to the center line of the left lane and the standard lane half-width), and the current right rear percentage ProbInRight_1 (representing the percentage of the lateral distance from the center of the rear axle of the rear vehicle in the right lane at the current moment to the center line of the right lane and the standard lane half-width).

[0195] If the rear vehicle in the right lane simultaneously meets the following conditions: (1) the current right rear percentage of the rear vehicle in the right lane ProbInRight_1 < 1, and within the first duration (such as within 3 seconds), ProbInRight_1 are all less than 1; (2) the current left rear percentage of the rear vehicle in the right lane ProbInLeft_1 > 2, and the current rear percentage ProbInEgo_1 > 1, and within the first duration (such as within 3 seconds), ProbInLeft_1 > 2 and ProbInEgo_1 > 1 are all satisfied. If the rear vehicle in the right lane simultaneously meets the above conditions (1) and (2), then it can be determined that the current driving state of the rear vehicle in the right lane is the lane keeping state.

[0196] If the rear vehicle in the right lane simultaneously meets the following conditions: (3) the current right rear percentage of the rear vehicle in the right lane ProbInRight_1 > 1, and ProbInRight_1Greater than the historical right-rear percentage in the Mth (where M is set to 100) cycle before the current cycle (i.e., 2 seconds ago); (4) The current left-rear percentage of the vehicle behind in the right lane ProbInLeft_1 Greater than the historical left-rear percentage in the Mth (where M is set to 100) cycle before the current cycle (i.e., 2 seconds ago), and the current own-rear percentage ProbInEgo_1 Greater than the historical own-rear percentage in the Mth (where M is set to 100) cycle before the current cycle (i.e., 2 seconds ago). If the vehicle behind in the right lane simultaneously meets the above conditions (3) and (4), then the current driving state of the vehicle behind in the right lane can be determined to be a right lane change driving state.

[0197] If the vehicle behind in the right lane simultaneously meets the following conditions: (5) The current right-rear percentage of the vehicle behind in the right lane ProbInRight_1 > 0, and continuously increases within the first duration (such as within 3 seconds) ProbInRight_1 ; (6) The current left-rear percentage of the vehicle behind in the right lane ProbInLeft_1 and the current own-rear percentage ProbInEgo_1 both continuously decrease within the first duration (such as within 3 seconds). If the vehicle behind in the right lane simultaneously meets the above conditions (5) and (6), then the current driving state of the vehicle behind in the right lane can be determined to be a left lane change driving state.

[0198] In some embodiments, if the vehicle behind is the vehicle behind in the right lane and the current driving state is a lane keeping state, then the third longitudinal safety distance between the vehicle behind in the right lane and the own vehicle can be calculated with reference to the above formula (23) . With reference to the above formula (26), based on the third longitudinal safety distance determine the fifth risk coefficient of the vehicle behind in the right lane affecting the realization of the assisted driving function of the own vehicle .

[0199] Since the vehicle behind in the right lane is located in the adjacent lane (such as the right lane), the final risk coefficient of the vehicle behind in the adjacent lane affecting the realization of the assisted driving function of the own vehicle can be determined according to formula (31).

[0200] _final=min(1,max(0, -offset 2 )) (31);

[0201] In formula (31), _final represents the final risk coefficient of the vehicle behind in the adjacent lane (such as the vehicle behind in the right lane) affecting the realization of the assisted driving function of the own vehicle; offset 2 represents a preset second offset term, and its value is generally a value greater than 0. For example, it can be set to 0.2, etc.

[0202] In some embodiments, according to the current lateral distance between the vehicle behind and the center line of this lane, and the current lateral distance between the vehicle behind and the center line of the adjacent lane, the risk coefficient of the vehicle behind affecting the vehicle to achieve the assisted driving function is evaluated, including:

[0203] If the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a right lane change driving state, then determine the sixth risk coefficient of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function;

[0204] If the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a left lane change driving state, then calculate the third imminent collision time between the vehicle behind in the right lane and the vehicle, and the lateral displacement distance of the vehicle behind in the right lane within the third imminent collision time;

[0205] Based on the third imminent collision time and the lateral displacement distance of the vehicle behind in the right lane, determine the seventh risk coefficient of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function.

[0206] If the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a right lane change driving state, it indicates that at this time the vehicle behind in the right lane moves away from the vehicle on this lane to the right. The sixth risk coefficient of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function 6 Can be set to 0.

[0207] If the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a left lane change driving state, it indicates that at this time the vehicle behind in the right lane is approaching laterally to this lane. At this time, the third imminent collision time between the vehicle behind in the right lane and the vehicle can be calculated with reference to the above formula (21), and the risk coefficient 1 of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function can be determined with reference to the above formula (24); the lateral displacement distance that the vehicle behind in the right lane can move within the third imminent collision time can be calculated with reference to the above formula (27), and the risk coefficient 2 of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function can be determined based on this lateral displacement distance.

[0208] Exemplarily, the seventh risk coefficient of the vehicle behind in the right lane affecting the vehicle to achieve the assisted driving function can be determined according to formula (32).

[0209] =min(1,max( B)） (32);

[0210] In formula (32), Represents the seventh risk coefficient of the vehicle behind in the right lane affecting the vehicle's implementation of the assisted driving function; Represents the risk coefficient 1 of the vehicle behind in the right lane affecting the vehicle's implementation of the assisted driving function; B Represents the risk coefficient 2 of the vehicle behind in the right lane affecting the vehicle's implementation of the assisted driving function.

[0211] In some embodiments, if the vehicle behind is a vehicle behind in the left lane and its current driving state is the lane-keeping state, then the risk coefficient of the vehicle behind in the left lane affecting the vehicle's implementation of the assisted driving function can be determined by referring to the case where the vehicle behind is a vehicle behind in the right lane and its current driving state is the lane-keeping state, which will not be elaborated here.

[0212] In some embodiments, if the vehicle behind is a vehicle behind in the left lane and its current driving state is the left lane-changing driving state, then the risk coefficient of the vehicle behind in the left lane affecting the vehicle's implementation of the assisted driving function can be determined by referring to the case where the vehicle behind is a vehicle behind in the right lane and its current driving state is the right lane-changing driving state, which will not be elaborated here.

[0213] In some embodiments, if the vehicle behind is a vehicle behind in the left lane and its current driving state is the right lane-changing driving state, then the risk coefficient of the vehicle behind in the left lane affecting the vehicle's implementation of the assisted driving function can be determined by referring to the case where the vehicle behind is a vehicle behind in the right lane and its current driving state is the left lane-changing driving state, which will not be elaborated here.

[0214] All the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present application, which will not be elaborated one by one here.

[0215] The following is an embodiment of the device of the present application, which can be used to execute the method embodiment of the present application. For details not disclosed in the device embodiment of the present application, please refer to the method embodiment of the present application.

[0216] Figure 8 Is a schematic diagram of a risk coefficient evaluation device for a vehicle behind provided by an embodiment of the present application. As Figure 8 shown, the risk coefficient evaluation device 800 for the vehicle behind includes:

[0217] An acquisition module 801, configured to acquire the driving trajectory of the vehicle in its own lane;

[0218] A first determination module 802, configured to determine the center line of its own lane and the center line of the adjacent lane based on the driving trajectory of the vehicle in its own lane;

[0219] The second determination module 803 is configured to determine the rear vehicle area and the rear vehicle. The rear vehicle is located within the rear vehicle area, and the rear vehicle area is located behind the rearward division line of the parallel area of the vehicle. The rearward division line of the parallel area is obtained by extending a preset rearward distance backward along the driving direction of the vehicle with the center of the rear axle of the vehicle as the coordinate origin.

[0220] The evaluation module 804 is configured to, when the vehicle is in the lane keeping state, evaluate the risk coefficient of the rear vehicle affecting the vehicle's implementation of the assisted driving function according to the current vehicle-rear lateral distance of the rear vehicle to the center line of the current lane and the current adjacent-vehicle-rear lateral distance of the rear vehicle to the center line of the adjacent lane.

[0221] In some embodiments, the above-mentioned evaluation module 804 includes:

[0222] The first determination unit is configured to, if the rear vehicle is a rear vehicle in the current lane, determine the current driving state of the rear vehicle in the current lane according to the current vehicle-rear lateral distance of the rear vehicle in the current lane to the center line of the current lane and the current adjacent-vehicle-rear lateral distance of the rear vehicle in the current lane to the center line of the adjacent lane.

[0223] The second determination unit is configured to, if the current driving state is the lane keeping state, determine at least one of the first imminent collision time, the first time-to-distance, or the first longitudinal safety distance between the rear vehicle in the current lane and the vehicle.

[0224] The third determination unit is configured to determine the first risk coefficient of the rear vehicle in the current lane affecting the vehicle's implementation of the assisted driving function based on at least one of the first imminent collision time, the first time-to-distance, or the first longitudinal safety distance.

[0225] In some embodiments, the above-mentioned first determination unit includes:

[0226] The calculation component is configured to calculate the current vehicle-rear percentage between the current vehicle-rear lateral distance and the standard lane half-width, and calculate the current adjacent-vehicle-rear percentage between the current adjacent-vehicle-rear lateral distance and the standard lane half-width.

[0227] The determination component is configured to determine the current driving state of the rear vehicle in the current lane according to the current vehicle-rear percentage and the current adjacent-vehicle-rear percentage.

[0228] In some embodiments, the center line of the adjacent lane includes the center line of the left lane and the center line of the right lane; the current adjacent-vehicle-rear lateral distance includes the current left-rear lateral distance and the current right-rear lateral distance. The current left-rear lateral distance represents the lateral distance of the rear vehicle to the center line of the left lane, and the current right-rear lateral distance represents the lateral distance of the rear vehicle to the center line of the right lane; the current adjacent-vehicle-rear percentage includes the current left-rear percentage and the current right-rear percentage. The above-mentioned determination component includes:

[0229] The first determination device is configured to determine that the current driving state of the vehicle behind in the current lane is the lane-keeping state if the current rear percentage of the vehicle is less than 1 and has been less than 1 within the first duration, and the current left-rear percentage and the current right-rear percentage are greater than 1 and have been greater than 1 within the first duration;

[0230] The second determination device is configured to determine that the current driving state of the vehicle behind in the current lane is the left-lane changing driving state if the current rear percentage of the vehicle is greater than 1, the current rear percentage of the vehicle is greater than the historical rear percentage of the vehicle in the Mth cycle before the current cycle, the current left-rear percentage is less than the historical left-rear percentage of the vehicle in the Mth cycle before the current cycle, and the current right-rear percentage is greater than the historical right-rear percentage of the vehicle in the Mth cycle before the current cycle;

[0231] The third determination device is configured to determine that the current driving state of the vehicle behind in the current lane is the right-lane changing driving state if the current rear percentage of the vehicle is greater than 1, the current rear percentage of the vehicle is greater than the historical rear percentage of the vehicle in the Mth cycle before the current cycle, the current left-rear percentage is greater than the historical left-rear percentage of the vehicle in the Mth cycle before the current cycle, and the current right-rear percentage is less than the historical right-rear percentage of the vehicle in the Mth cycle before the current cycle, where M is a positive integer.

[0232] In some embodiments, the above-mentioned evaluation module 804 further includes:

[0233] The first calculation unit is configured to calculate the second imminent collision time between the vehicle behind in the current lane and the vehicle itself, and the lateral displacement distance of the vehicle behind in the current lane within the second imminent collision time if the current driving state is the left-lane changing driving state;

[0234] The judgment unit is configured to determine whether the vehicle behind in the current lane can completely drive into the left lane within the second imminent collision time based on the lateral displacement distance;

[0235] The first coefficient determination unit is configured to determine the second risk coefficient of the vehicle behind in the current lane affecting the vehicle itself to achieve the assisted driving function if it can;

[0236] The second coefficient determination unit is configured to determine the third risk coefficient of the vehicle behind in the current lane affecting the vehicle itself to achieve the assisted driving function based on the lateral displacement distance if it cannot, and the third risk coefficient is greater than the second risk coefficient.

[0237] In some embodiments, the above-mentioned second coefficient determination unit includes:

[0238] The coefficient calculation component is configured to calculate the second longitudinal safety distance between the vehicle behind in the current lane and the vehicle itself, and determine the fourth risk coefficient of the vehicle behind in the current lane affecting the vehicle itself to achieve the assisted driving function based on the second longitudinal safety distance;

[0239] A coefficient determination component configured to determine a final risk coefficient of a vehicle behind in the current lane affecting the vehicle's implementation of an assisted driving function based on a third risk coefficient, a fourth risk coefficient, and a preset first offset term.

[0240] In some embodiments, the above-mentioned evaluation module 804 includes:

[0241] A distance calculation unit configured to calculate a third longitudinal safety distance between the vehicle behind in the adjacent lane and the vehicle itself if the vehicle behind is a vehicle behind in the adjacent lane and the current driving state of the vehicle behind in the adjacent lane is a lane-keeping state.

[0242] A third coefficient determination unit configured to determine a fifth risk coefficient of the vehicle behind in the adjacent lane affecting the vehicle's implementation of an assisted driving function based on the third longitudinal safety distance and a preset second offset term.

[0243] In some other embodiments, the above-mentioned evaluation module 804 includes:

[0244] A fourth coefficient determination unit configured to determine a sixth risk coefficient of the vehicle behind in the right lane affecting the vehicle's implementation of an assisted driving function if the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a right lane change driving state.

[0245] A second calculation unit configured to calculate a third time-to-collision and a fourth longitudinal safety distance between the vehicle behind in the right lane and the vehicle itself if the vehicle behind is a vehicle behind in the right lane and the current driving state of the vehicle behind in the right lane is a left lane change driving state.

[0246] A fifth coefficient determination unit configured to determine a seventh risk coefficient of the vehicle behind in the right lane affecting the vehicle's implementation of an assisted driving function based on the third time-to-collision and the fourth longitudinal safety distance.

[0247] In some embodiments, the above-mentioned first determination module 802 includes:

[0248] An update unit configured to establish a current vehicle coordinate system based on the current position of the vehicle itself and update the relative positions of the respective lane driving trajectory points of the lane driving trajectory in the current vehicle coordinate system.

[0249] A center line determination unit configured to determine the center line of the current lane and the center line of the adjacent lane based on the relative positions.

[0250] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not imply the order of execution. The order of execution of each process should be determined based on its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0251] Figure 9 is a schematic diagram of the electronic device 900 provided by an embodiment of the present application. As Figure 9 shown, the electronic device 900 of this embodiment includes: a processor 901, a memory 902, and a computer program 903 stored in the memory 902 and executable on the processor 901. When the processor 901 executes the computer program 903, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor 901 executes the computer program 903, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0252] The electronic device 900 may be a desktop computer, a notebook, a palm computer, a cloud server, or other electronic devices. The electronic device 900 may include, but is not limited to, the processor 901 and the memory 902. Those skilled in the art can understand that Figure 9 merely examples of the electronic device 900, and do not constitute a limitation to the electronic device 900, which may include more or fewer components than shown in the figure, or different components.

[0253] The processor 901 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0254] The memory 902 may be an internal storage unit of the electronic device 900. For example, the hard disk or memory of the electronic device 900. The memory 902 may also be an external storage device of the electronic device 900. For example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 900. The memory 902 may also include both an internal storage unit and an external storage device of the electronic device 900. The memory 902 is used to store computer programs and other programs and data required by the electronic device.

[0255] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0256] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, to implement all or part of the processes in the above-mentioned embodiment methods of this application, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in the readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. The computer program can include computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0257] The above embodiments are only used to illustrate the technical solutions of this application, not to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of this application, and should all be included in the protection scope of this application.

Claims

1. A risk coefficient evaluation method for a following vehicle, characterized in that, Including: Obtain the driving trajectory of the vehicle in its own lane; Based on the driving trajectory of the vehicle in its own lane, determine the center line of the own lane and the center lines of adjacent lanes; Determine the rear vehicle area and the rear vehicle. The rear vehicle is located within the rear vehicle area, and the rear vehicle area is behind the rearward dividing line of the parallel area of the vehicle. The rearward dividing line of the parallel area is obtained by taking the center of the rear axle of the vehicle as the coordinate origin and extending a preset rearward distance along the driving direction of the vehicle; When the vehicle is in the lane keeping state, if the rear vehicle is a rear vehicle in the own lane, then according to the current own-rear lateral distance between the rear vehicle in the own lane and the center line of the own lane and the current own-rear percentage between the standard lane half-width, and the current adjacent-rear lateral distance between the rear vehicle in the own lane and the center line of the adjacent lane and the current adjacent-rear percentage between the standard lane half-width, determine the current driving state of the rear vehicle in the own lane; Based on the current driving state of the rear vehicle in the own lane, evaluate the risk coefficient of the rear vehicle in the own lane affecting the vehicle to achieve the assisted driving function.

2. The method according to claim 1, wherein Based on the current driving state of the rear vehicle in the own lane, evaluating the risk coefficient of the rear vehicle in the own lane affecting the vehicle to achieve the assisted driving function includes: If the current driving state is the lane keeping state, then determine at least one of the first imminent collision time, the first distance-time, or the first longitudinal safety distance between the rear vehicle in the own lane and the vehicle; the first distance-time is used to indicate the safe distance and safe time to be maintained between the rear vehicle in the own lane and the vehicle; Based on at least one of the first imminent collision time, the first distance-time, or the first longitudinal safety distance, determine the first risk coefficient of the rear vehicle in the own lane affecting the vehicle to achieve the assisted driving function.

3. The method according to claim 1, characterized in that The center lines of the adjacent lanes include the center line of the left lane and the center line of the right lane; the current adjacent-rear lateral distance includes the current left-rear lateral distance and the current right-rear lateral distance. The current left-rear lateral distance represents the lateral distance from the rear vehicle to the center line of the left lane, and the current right-rear lateral distance represents the lateral distance from the rear vehicle to the center line of the right lane; the current adjacent-rear percentage includes the current left-rear percentage and the current right-rear percentage; According to the current own-rear lateral distance between the rear vehicle in the own lane and the center line of the own lane and the current own-rear percentage between the standard lane half-width, and the current adjacent-rear lateral distance between the rear vehicle in the own lane and the center line of the adjacent lane and the current adjacent-rear percentage between the standard lane half-width, determining the current driving state of the rear vehicle in the own lane includes: If the current own-rear percentage is less than 1 and is less than 1 within the first duration, and the current left-rear percentage and the current right-rear percentage are greater than 1 and are greater than 1 within the first duration, then determine that the current driving state of the rear vehicle in the own lane is the lane keeping state; If the current rear percentage of this lane is greater than 1 and the current rear percentage of this lane is greater than the historical rear percentage of the M-th cycle before the current cycle, and the current left rear percentage is less than the historical left rear percentage of the M-th cycle before the current cycle, and the current right rear percentage is greater than the historical right rear percentage of the M-th cycle before the current cycle, then determine that the current driving state of the vehicle behind in this lane is a left lane change driving state; If the current rear percentage of this lane is greater than 1, and the current rear percentage of this lane is greater than the historical rear percentage of the M-th cycle before the current cycle, and the current left rear percentage is greater than the historical left rear percentage of the M-th cycle before the current cycle, and the current right rear percentage is less than the historical right rear percentage of the M-th cycle before the current cycle, then determine that the current driving state of the vehicle behind in this lane is a right lane change driving state, where M is a positive integer.

4. The method according to claim 1, characterized in that Based on the current driving state of the vehicle behind in this lane, evaluate the risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle, including: If the current driving state is a left lane change driving state, then calculate the second time to imminent collision between the vehicle behind in this lane and this vehicle, and the lateral displacement distance of the vehicle behind in this lane within the second time to imminent collision; Based on the lateral displacement distance, determine whether the vehicle behind in this lane can completely drive into the left lane within the second time to imminent collision; If so, determine the second risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; If not, then based on the lateral displacement distance, determine the third risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle, and the third risk coefficient is greater than the second risk coefficient.

5. The method according to claim 4, characterized in that, After determining the third risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle based on the lateral displacement distance, it further includes: Calculate the second longitudinal safety distance between the vehicle behind in this lane and this vehicle, and based on the second longitudinal safety distance, determine the fourth risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle; Based on the third risk coefficient, the fourth risk coefficient and a preset first offset term, determine the final risk coefficient of the vehicle behind in this lane affecting the realization of the assisted driving function of this vehicle.

6. The method according to claim 1, characterized in that After determining the rear vehicle area and the vehicle behind, it further includes: When this vehicle is in the lane keeping state, if the vehicle behind is the vehicle behind in the adjacent lane and the current driving state of the vehicle behind in the adjacent lane is the lane keeping state, then calculate the third longitudinal safety distance between the vehicle behind in the adjacent lane and this vehicle; Based on the third longitudinal safety distance and a preset second offset term, determine the fifth risk coefficient of the vehicle behind in the adjacent lane affecting the realization of the assisted driving function of this vehicle.

7. The method according to claim 1, wherein After determining the rear vehicle area and the vehicle behind, it further includes: When the host vehicle is in the lane keeping state, if the rear vehicle is a rear vehicle in the right lane and the current driving state of the rear vehicle in the right lane is a right lane change driving state, determine a sixth risk coefficient of the rear vehicle in the right lane affecting the host vehicle to realize the assisted driving function; If the rear vehicle is a rear vehicle in the right lane and the current driving state of the rear vehicle in the right lane is a left lane change driving state, calculate a third time to imminent collision and a fourth longitudinal safety distance between the rear vehicle in the right lane and the host vehicle; Based on the third time to imminent collision and the fourth longitudinal safety distance, determine a seventh risk coefficient of the rear vehicle in the right lane affecting the host vehicle to realize the assisted driving function.

8. The method according to claim 1, wherein Based on the driving trajectory of the host lane, determine the center line of the host lane and the center line of the adjacent lane, including: Establish a current vehicle coordinate system based on the current position of the host vehicle, and update the relative positions of the respective host lane driving trajectory points of the driving trajectory of the host lane in the current vehicle coordinate system; Based on the relative positions, determine the center line of the host lane and the center line of the adjacent lane.

9. A risk coefficient evaluation device for a rear vehicle, characterized in that, Including: An acquisition module configured to acquire the driving trajectory of the host lane of the host vehicle; A first determination module configured to determine the center line of the host lane and the center line of the adjacent lane based on the driving trajectory of the host lane; A second determination module configured to determine a rear vehicle area and a rear vehicle. The rear vehicle is located within the rear vehicle area, and the rear vehicle area is located behind the rearward dividing line of the parallel area of the host vehicle. The rearward dividing line of the parallel area is obtained by extending a preset rearward distance along the driving direction of the host vehicle with the center of the rear axle of the host vehicle as the coordinate origin; An evaluation module configured to, when the host vehicle is in the lane keeping state, if the rear vehicle is a rear vehicle in the host lane, determine the current driving state of the rear vehicle in the host lane according to the current host-rear lateral distance between the rear vehicle in the host lane and the center line of the host lane and the current host-rear percentage between the current host-rear lateral distance and the standard lane half-width, and the current adjacent-rear lateral distance between the rear vehicle in the host lane and the center line of the adjacent lane and the current adjacent-rear percentage between the current adjacent-rear lateral distance and the standard lane half-width; and evaluate the risk coefficient of the rear vehicle in the host lane affecting the host vehicle to realize the assisted driving function based on the current driving state of the rear vehicle in the host lane.

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