METHOD FOR SAFETY ASSESSMENT OF A LANE CHANGE MANEUVER IN AUTOMATED DRIVING OPERATION OF A VEHICLE

Description

[0001] The invention relates to methods for the safety assessment of a lane change maneuver in the automated driving operation of a vehicle with environmental sensors, wherein the environment of the vehicle and objects located therein are detected on the basis of signals recorded by the environmental sensors.

[0002] The closest prior art to the invention is a method for the safety assessment of a lane-change maneuver in automated driving mode using environmental sensors, as described in US 2020 / 361452 A1. In this method, objects in the vehicle's vicinity are detected using the environmental sensors, and a collision risk with other vehicles is determined before a lane-change maneuver from one of the outer lanes to the middle lane of a multi-lane roadway. For this purpose, hypothetical lane-change maneuvers of the other vehicles are calculated.

[0003] US 2018 / 188735 A1 discloses a lane-change system that controls the steering of the vehicle and aborts a lane-change maneuver as soon as it detects a high risk of collision with another vehicle.

[0004] The prior art comprises a method for operating a motor vehicle during a lane change on a roadway with at least three lanes, as described in DE 10 2013 010183 A1. The method detects the impending lane changes of the motor vehicle and any other vehicles and detects an impending collision.

[0005] US Patent 8,244,408 B2 discloses a method for assessing the risk associated with the operation of an autonomous vehicle control system. A vehicle is configured to perform an autonomous lane-change maneuver and is equipped with a monitoring system. This system monitors each of several objects located near the vehicle. The positions of each object are predicted relative to a projected trajectory of the vehicle, and a collision risk level between the vehicle and each object is assessed.

[0006] The invention is based on the objective of providing a novel method for the safety assessment of a lane change maneuver in the autonomous driving operation of a vehicle.

[0007] The problem is solved according to the invention by a method which has the features specified in claim 1.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] A method for the safety assessment of a lane change maneuver in the autonomous driving mode of a vehicle with environmental sensors, wherein the environment of the vehicle and objects located therein are detected on the basis of acquired signals from the environmental sensors, provides according to the invention that Prior to an initiated lane change maneuver by the vehicle from a left lane to a middle lane or from a right lane to a middle lane of a multi-lane roadway section, a collision risk is determined by means of hypothetical lane change maneuvers by other vehicles in the right or left lane, whereby longitudinal accelerations are calculated based on a maximum lane change duration and a shearing moment, which lead to a collision due to an overlap of the vehicle surfaces of the vehicle and the other vehicles.The execution of the lane-change maneuver is evaluated based on the vehicle's relative longitudinal position to other vehicles and its relative longitudinal speeds to other vehicles at the start of the maneuver, using a collision probability as a safety measure and a minimum distance to avoid a collision as a further safety measure.

[0010] In particular, the procedure provides for a check, even before the vehicle begins changing lanes, to determine whether a lane change can still be carried out safely, even if the vehicle misjudges the likelihood of other vehicles changing lanes or if a lane change is unpredictable due to the context. For this reason, the probability of a collision is determined solely based on longitudinal acceleration, as the lane changes of other vehicles cannot be predicted.

[0011] By applying this method, the collision risk of a vehicle can be assessed / quantified at a tactical level for carrying out a lane change maneuver to the middle lane.

[0012] A vehicle's automated, and especially autonomous, driving system can reduce the risk of collision even before the lane change maneuver by adjusting its target behavior, or postpone the start of the lane change maneuver if both positive and negative acceleration costs for the vehicle are too high and / or until the initial situation for a safe lane change has improved.

[0013] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0014] This shows: Fig. 1 schematically shows a roadway section with three lanes and two vehicles, Fig. 2 schematically shows two illustrations of the roadway section with the same initial situation and a different longitudinal acceleration, Fig. 3 schematically shows a derivation of the shearing moment in a specific situation, Fig. 4 schematically shows a derivation of the shearing moment in another specific situation, Fig. 5 schematically shows a derivation of the shearing moment in another specific situation, Fig. 6 schematically shows a derivation of the shearing moment in another specific situation, Fig. 7 schematically shows limit cases for starting positions and their relative longitudinal speed profiles, Fig. 8 schematically shows a derivation of a collision probability as a safety measure, Fig.Figure 9 shows a schematic representation of a calculation of a minimum distance between the vehicle and the next vehicle in the next-but-one lane as a further safety measure, and Figure 10 shows a schematic representation of different limiting cases for calculating longitudinal acceleration limits.

[0015] Corresponding parts are marked with the same reference symbols in all figures.

[0016] Figur 1 Figure 1 shows a roadway section F with three lanes F1 to F3 running in the same direction. A vehicle EGO is driving autonomously in the left lane F1 and intends to perform a lane change maneuver to the middle lane F2. The figure shows the lane change trajectory T1 of vehicle EGO from the left lane F1 to the middle lane F2.

[0017] On the right-hand lane F3, another vehicle PE1 is traveling, which may, even without a discernible intention, attempt a lane change maneuver to the middle lane F2. A hypothetical lane change trajectory T2 of the other vehicle PE1 from the right-hand lane F3 to the middle lane F2 is also shown. A lane-following trajectory ST of the other vehicle PE1, which exclusively concerns the right-hand lane F3, is also shown. Figur 1 shown.

[0018] For automated, and especially autonomous, driving of a vehicle (EGO), changing lanes is a comparatively complex maneuver. This requires planning and executing the longitudinal and lateral movements of the vehicle (EGO) while taking the surrounding environment into account.

[0019] According to Donges and Michon, it is known that the evaluation of a lane-change maneuver takes place on three levels: a strategic, a tactical, and an operational level. The following problem description refers specifically to the tactical level, which describes the attractiveness and feasibility of a lane-change maneuver. Typically, an autonomous lane change is analyzed at this level only by including object information that corresponds to the user's own, as in the present embodiment, Figur 1 The left lane F1 and a destination lane ZS, i.e., the middle lane F2, are assigned. Object information for other vehicles PE1 to PE3, shown in the following figures, on the next-but-one lane, i.e., the right lane F3, is not considered, or only indirectly, for example via potential fields, if a predicted behavior is irrelevant to the destination lane ZS. The number of these other vehicles PE1 to PE3 is not fixed at 3 and can vary. Therefore, erroneous predictions or lane changes that are not apparent from the context are either not considered or only taken into account by generic fallback trajectories.During lane-changing maneuvers on three- or multi-lane road sections F, particularly on a motorway, from a left lane F1 or a right lane F3 to the middle lane F2, it can happen that another vehicle PE1 to PE3 decides to change to the same destination lane ZS at the same time, even without any apparent intention. Such a case represents a comparatively critical situation.

[0020] During lane-changing maneuvers, there is therefore a risk of collision with other vehicles PE1 to PE3 that could change to the middle lane F2 at the same time.

[0021] While a human driver of the vehicle EGO, based on their previous experience, anticipates the behavior of surrounding traffic during lane-changing maneuvers, also taking into account objects, i.e., road users, on the next lane but one, in relation to Figur 1 While a human driver can assess the situation on the right-hand lane F3 in order to evaluate its tactical driving decision in terms of attractiveness and feasibility, automated vehicle systems rely on rule sets that evaluate a planned tactical behavior based on measurement data from environmental sensors.

[0022] In particular, there is neither a risk quantification, especially in the form of a safety measure S1, S2, nor a calculation rule for a desired target behavior of the automated driving system of the vehicle EGO.

[0023] To evaluate a lane change maneuver to the middle lane F2 at a tactical level, taking into account object information on the next lane (the right lane F3), it is therefore necessary to define metrics and parameters that allow for the quantification of the collision risk of these objects during lane change maneuvers. Based on this, a desired target behavior for the automated driving system can then be derived.

[0024] The following describes a method for the safety assessment of a lane change maneuver in the autonomous driving operation of the vehicle EGO using environmental sensors, whereby the environment of the vehicle EGO and objects located within it are detected based on signals recorded by the environmental sensors.

[0025] For the purpose of carrying out the procedure, it is assumed that lane-changing maneuvers of further vehicles PE1 to PE3 cannot be predicted.

[0026] In Figur 2 are two images A1, A2 with a road section F and the same initial situation Δ x MM,init,PEi , Δ v x,init,PEi The diagram shows vehicle EGO traveling in the left lane F1 and intending to change lanes to the middle lane F2. Three other vehicles, PE1 to PE3, are traveling in the right lane F3.

[0027] A lane change maneuver by vehicle EGO into the middle lane F2 is analyzed for potential collisions using hypothetical lane change maneuvers by other vehicles PE1 to PE3. These other vehicles can be passenger cars or trucks. This means that each of the other vehicles PE1 to PE3 represents a potential merging vehicle for vehicle EGO. The other vehicles PE1 to PE3 can also be other modes of transport, such as motorcycles. In these cases, acceleration ranges are determined, and the same principle for risk analysis regarding a lane change by vehicle EGO is applied.

[0028] To verify the lane-change maneuver using the hypothetical lane-change maneuvers of the other vehicles PE1 to PE3, longitudinal accelerations ax,PE are calculated using linearized cross-sectional profiles, specifically based on a maximum lane-change duration and a shearing moment. These accelerations are designed to lead to a collision due to an overlap of vehicle surfaces between vehicle EGO and one of the other vehicles PE1 to PE3. It is defined that the probability of occurrence of the respective longitudinal accelerations ax,PE leading to a collision simultaneously describes, or corresponds to, the probability of a collision, since the longitudinal acceleration ax,PE is directly related to an overlap of vehicle surfaces and thus to a collision.

[0029] An evaluation of the lane-changing maneuver at the tactical level depends on a relative longitudinal position Δ x MM,init,PEi , also referred to as the initial distance between vehicle centers, as vehicle measurement variable 1 and an initial relative longitudinal speed Δ v x,init,PEi as vehicle measurement parameter 2 at the start of the lane change maneuver based on two safety measures S1, S2.

[0030] This results in the relative longitudinal position Δ x MM,init,PEi as follows: Δ x MM , init , PE i = x M , EGO , init − x M , PE i , init

[0031] The initial relative longitudinal velocity Δ v x,init,PEi is calculated as follows: Δ v x , init , PE i = v x , EGO , init − v x , PE i , init

[0032] In particular, an initial longitudinal distance is negative if the vehicle EGO is traveling behind another vehicle PE1 to PE3. The same applies to a relative speed Δ. v x ( t SP ) , which is positive if the vehicle EGO has a higher longitudinal speed v x,EGO, init exhibits, as another vehicle PE1 to PE3.

[0033] A safety measure S1 represents a probability of collision, and a further safety measure S2 represents, if no collision is imminent, a minimum distance dx,min between the vehicle EGO and the other vehicles PE1 to PE3.

[0034] An assessment of the collision probability as a safety measure S1 is based on a collision probability derived from a previously determined

[0035] Probability of expected longitudinal accelerations ax,PE of the other vehicles PE1 to PE3, based on the initial situation Δ x MM,init,PEi , Δ v x,init,PEi , based on geometric vehicle information l EGO of the vehicle EGO, a geometric vehicle information l PE the other vehicles PE1 to PE3, based on the lane change start times of the other vehicles PE1 to PE3, a duration of the lane change maneuver and a planned longitudinal acceleration ax,EGO,n of the vehicle EGO.

[0036] An assessment of the minimum distance dx,min as a further safety measure S2 is based on the minimum longitudinal distance between the nearest bumpers. The minimum distance dx,min is selected throughout the entire lane-change maneuver after the lateral coordinates between vehicle EGO and at least one other vehicle PE1 to PE3 intersect.

[0037] The calculation of the two safety measures S1 and S2 is model-based.

[0038] By changing the longitudinal acceleration ax,EGO,n , represented by the index n, and / or a lane change duration, the vehicle EGO can influence the collision probability and the minimum distance dx,min during the lane change maneuver.

[0039] In a first figure A1, a scenario with three further vehicles PE1 to PE3 as potential mergers into the middle lane F2 is shown in their respective initial situation Δ x MM,init,PE i , Δ v x ,init,PE i shown.

[0040] A total collision probability P G Kol,PE i , n > 0 of vehicle EGO exists for vehicle EGO with another first vehicle PE1, where in the first figure A1 a minimum distance dx,min to the respective other vehicle PE1 to PE3 applies at a longitudinal acceleration a ,x,EGO,0, which at a total collision probability P GKol,PE i,n > 0 is set to zero.

[0041] In a second figure A2 in Figur 2 is the same initial situation Δ x MM,init,PE i , Δ v x ,init,PE i as shown in the first figure A1. The vehicle EGO exhibits a changed longitudinal acceleration ax,EGO,n, resulting in new values ​​for the respective collision probability and the respective minimum distance dx,min.

[0042] The vehicle EGO is therefore able to reduce the risk of a collision even before the lane change maneuver has been initiated, or to deliberately postpone the start of the lane change maneuver if the positive or negative acceleration effort of the vehicle EGO is too high and / or until the initial situation for a safe lane change has improved.

[0043] To carry out the procedure, a definition of a start time and an end time for the lane change maneuver is required in order to distinguish each scenario from others. These times are determined according to the procedure known from source: Vasile, Laurin, Kiran Divakar, and Dieter Schramm. Deep-Learning Based Behavior Prediction of Rear-Rearing Vehicles for Highly Automated Lane Changes. Transforming Mobility - What Next? - Proceedings of the 13th Science Forum Mobility: Springer Fachmedien Wiesbaden, 2021.

[0044] Using a defined start and end time of a lane change maneuver, average longitudinal accelerations are determined from a real-world driving dataset based on the recorded measurement data. This calculation depends on the lane change direction, particularly in relation to a faster / slower lane (F1 to F3), and the vehicle class. Furthermore, the probability of an average longitudinal acceleration being used for the lane change maneuver is also determined. This is achieved by generating a probability density function based on a frequency distribution, depending on the lane change direction and vehicle class. pdf A probability density function was created whose integral describes the probability of a corresponding acceleration range. pdf is then applied to the other vehicles PE1 to PE3 depending on the lane change direction and their vehicle class.

[0045] Based on the measurement data, a lane change duration is further calculated using the start and end times. t PE (Δ y PE,ZM ) depending on a distance Δ y PE, ZM The lane change duration is determined by the vehicle PE1 to PE3 traveling to a target lane center ZM, by a lane change direction, particularly in relation to a faster / slower lane F1 to F3, and by a vehicle class. t PE (Δ y ZM ) is achieved through several lane-changing maneuvers that maintain a similar distance Δ y PE, ZM The distance to the target track center ZM is determined by averaging.

[0046] Using the determined longitudinal acceleration, a model is developed which calculates the collision probability as a safety measure S1 and the minimum distance dx,min between the vehicle EGO and the other vehicles PE1 to PE3 as a further safety measure S2, based on a respective initial situation Δ x MM,init,PE i , Δ v x,init,PE i can be determined, in particular calculated, and which influence possibilities of the vehicle EGO through changes in its longitudinal acceleration ax,EGO,n are taken into account.

[0047] Longitudinal acceleration ranges and their probabilities are used to calculate the collision probability as a safety measure S1. This involves checking which longitudinal accelerations ax,PE of the respective other vehicles PE1 to PE3 would lead to a collision with vehicle EGO during a lane change maneuver onto the middle lane F2.

[0048] Lane change maneuvers of the vehicle EGO are based on the initial situation Δ x MM,init,PE i , Δ v x ,init,PE i The situation is assessed in relation to one or more other vehicles PE1 to PE3 in the right-hand lane F3. This assessment is based on an initial distance Δ. x MM,init,PEi the two vehicle centers and an initial relative longitudinal speed Δ v x,init,PEi described. These two parameters are determined using signals from the environmental sensors of the automated, especially autonomous, driving vehicle EGO.

[0049] Based on the initial situation Δ x MM,init,PE i , Δ v x ,init,PE i Subsequently, a minimum longitudinal acceleration ax,PE,min and a maximum longitudinal acceleration ax,PE,max are determined for the other vehicles PE1 to PE3, for which a collision just barely occurs during a lane-change maneuver, assuming a linearized cross-sectional profile of vehicle EGO and the other vehicles PE1 to PE3. Values ​​within these longitudinal acceleration limits, including the limit values, also lead to a collision.

[0050] A necessary longitudinal acceleration range ax,PE,min to ax,PE,max of the further vehicle PE1 to PE3, which leads to a potential collision, can be influenced by the longitudinal acceleration ax,EGO, whereby different longitudinal accelerations ax,EGO,n are represented by the index n.

[0051] A period of time to be considered is defined by a maximum of the lane change duration (SWD) t Ego of the vehicle EGO and the other vehicles PE1 to PE3 t max = max ( t PE (Δ y ZM ), t Ego ) defined.

[0052] This is particularly true because a longer lane change duration provides more time to also achieve a higher initial relative longitudinal speed Δ v x,init,PEi and to reduce distances with a lower acceleration difference between the vehicle EGO and at least one of the other vehicles PE1 to PE3, which represents a more critical case. Such a case is described below. Furthermore, the start of the period under consideration, within which a collision can occur, is defined by a time point. t EM defined as a shearing-in process.

[0053] Around the time t EM To determine the merging process of both vehicles EGO, PE1 to PE3, i.e., the point in time at which the two vehicle surfaces first overlap laterally, lateral movements of vehicle EGO and the corresponding other vehicle PE1 to PE3 are linearized. Figuren 3 bis 6 Each illustrates a calculation rule and shows four possible cases.

[0054] Assuming a constant lateral velocity, the initial distance Δ can be used to determine... y PE, ZM Four possible times to the center of the finish line ZM t EM to calculate for a reeving operation. Case 1:

[0055] A in Figur 3 The illustrated embodiment shows possible points of intersection of resulting straight lines, which represent the linearized lateral movement of the vehicle-facing sides (ZF).

[0056] If the two vehicle surfaces overlap before the completion of one of the two lane-changing maneuvers, then the following applies: t EM = y ZF , Ego t SP − y ZF , PE , init v y , Ego + v y , PE Condition:

[0057] t EGO = y ZF , Ego , End − y ZF , Ego t SP v y , Ego ≥ t PE , FPC = y ZF , Ego , End − y ZF , PE , init v y , PE ∧ t PE Δ y ZM = y ZF , PE , End − y ZF , PE , init v y , PE + t SP > t EGO , FPC = y ZF , Ego , init − y ZF , PE , End v y , EGO

[0058] t SP This describes a shift in the start of the lane change by the corresponding other vehicle PE1 to PE3. By assuming that there are lane change maneuvers that cannot be recognized in context, the corresponding other vehicle PE1 to PE3 can decide to also change lanes F1 to F3 at any possible point during the lane change maneuver of vehicle EGO.

[0059] Due to the shift t SP If the start of the lane change by the corresponding further vehicle PE1 to PE3 is postponed to a later time, the period to be considered is shortened.

[0060] An initial position and relative velocity are calculated as follows: Δ x MM t SP = Δx MM , init , PE i + Δv x , init , PE i t SP + 1 2 a x , Ego , n − a x , PE i , init t SP 2 Δ v x t SP = Δ v x , init , PE i + a , Ego , n − a x , PE i , init t SP

[0061] It is assumed that the initial longitudinal acceleration a x,PEi,init The measurement of other vehicles PE1 to PE3 cannot be measured exactly or only inaccurately and is therefore assumed to be zero for the procedure described here. y ZF , EGO t SP = y ZF , EGO , init + v y , EGO t SP t SP ∈ 0 , t max − y SB , PE − y ZF , PE , init v y , PE

[0062] A first possible contact FPC between the vehicle EGO and the corresponding further vehicles PE1 to PE3 is in Figur 3 also shown as described. Case 2:

[0063] If the corresponding further vehicle PE1 to PE3 reaches a lateral end position of vehicle EGO after vehicle EGO has completed its lateral movement, but before the end of the considered period ( t max - t SP ), so the following applies: t EM = y ZF , Ego , End − y ZF , PE , init v y , PE Condition:

[0064] t PE Δ y ZM > t Ego ∧ t max − t SP ≥ t PE , FPC = y ZF , Ego , End − y ZF , PE , init v y , PE ≥ t EGO = y ZF , Ego , End − y ZF , Ego t SP v y , Ego as in the embodiment in Figur 4 shown. Case 3:

[0065] If the corresponding further vehicle PE1 to PE3 reaches the lateral end position only after the end of the considered period (t max - t SP), but still reaches the lane boundary within the considered period (t max - t SP ) ( y SB,PE ) of the target lane ZS, then: t EM = t max − t SP Condition:

[0066] t PE , FPC = y ZF , Ego , End − y ZF , PE , init v y , PE > t max − t SP ≥ t PE , SB = y SB , PE − y ZF , PE , init v y , PE .

[0067] Although there is no actual overlap between vehicle surfaces, the presence of both vehicles EGO, PE1 to PE3 next to each other in the same lane F2 is considered critical and consequently evaluated as an overlap. Case 4:

[0068] If the corresponding further vehicle PE1 to PE3 reaches its lateral end position before the vehicle EGO reaches a lateral end position of the corresponding further vehicle PE1 to PE3, then the following applies: t EM = y ZF , Ego t SP − y ZF , PE , End v y , Ego Condition:

[0069] t EGO , FPC − t SP = y ZF , Ego , init − y ZF , PE , End v y , EGO − t SP ≥ t PE Δ y ZM = y ZF , PE , End − y ZF , PE , init v y , PE

[0070] Case 4 is completed with equation (13).

[0071] A minimum longitudinal acceleration is calculated using the following formula. a x,PEi,min and a maximum longitudinal acceleration a x,PEi,max of the corresponding additional vehicle PE1 to PE3. Values ​​within these limits, including limit values, lead to, given the initial situation Δ x MM,init,PE i , Δv x ,init,PE i to a collision: Beschleunigungsdifferenzgrenzfälle: Δ a Gf , t max = − Δ v x t SP t max − t SP ; Δ a Grenzfall , t EM = − Δ v x t SP t EM Startpositiongrenzfälle ( Gf ): Δ x MM , Gf , t max = 1 2 Δ a Gf , t max t max − t SP 2 − L f ü r Δ v x t SP ≥ 0 1 2 Δ a Gf , t max t max − t SP 2 + L f ü r Δ v x t SP < 0 ; Δ x MM , Gf , t EM = 1 2 Δ a Gf , t max t EM 2 − L f ü r Δ v x t SP ≥ 0 1 2 Δ a Gf , t max t EM 2 + L f ü r Δ v x t SP < 0 Δ x MM , a min , equal = − Δ v x t SP t EM 1 + t EM t max − t SP + L f ü r Δ v x t SP ≥ 0 ; Δ x MM , a max , equal = − Δ v x t SP t EM 1 + t EM t max − t SP − L f ü r Δ v x t SP < 0 with: L = l EGO + l PE i 2 ; l EGO = Fahrzeugl ä nge EGO , l PE i = Fahrzeugl ä nge PE 1 bis PE 3 Δ x MM , t max = Δ x MM t SP + Δ v x t SP t max − t SP + 1 2 a x , Ego , n t max − t SP 2 ; Δ x MM , t EM = Δ x MM t SP + Δ v x t SP t EM + 1 2 a x , Ego , n t EM 2 (21a) (21b) a x , PE i , max = 2 Δ x MM , t max + L t max − t SP 2 f ü r Δ x MM t SP < Δ x MM , Gf , t max ∧ Δ v x t SP ≥ 0 ∨ Δ x MM t SP ≤ Δ x MM , a max , equal ∧ Δ v x t SP < 0 a x , Ego , n − 1 2 Δ v x 2 t SP Δ x MM t SP + L f ü r Δ x MM , Gf , t max ≤ Δ x MM t SP ≤ Δ x MM , Gf , t EM ∧ Δ v x t SP ≥ 0 2 Δ x MM , t EM + L t EM 2 f ü r Δ x MM , Gf , t EM < Δ x MM t SP ∧ Δ v x t SP ≥ 0 ∨ Δ x MM , a max , equal < Δ x MM t SP ∧ Δ v x t SP < 0 a x , PE i , min = 2 Δ x MM , t max − L t max − t SP 2 f ü r Δ x MM , Gf , t max ≤ Δ x MM t SP ∧ Δ v x t SP < 0 ∨ Δ x MM , a min , equal ≤ Δ x MM t SP ∧ Δ v x t SP ≥ 0 22 d a x , Ego , n − 1 2 Δ v x 2 t SP Δ x MM t SP − L f ü r Δ x MM , Gf , t EM ≤ Δ x MM t SP ≤ Δ x MM , Gf , t max ∧ Δ v x t SP < 0 22 e 2 Δ x MM , t EM − L t EM 2 f ü r Δ x MM t SP < Δ x MM , Gf , t EM ∧ Δ v x t SP < 0 ∨ Δ x MM t SP < Δ x MM , a min , equal ∧ Δ v x t SP ≥ 0 21 f

[0072] Figur 7 shows explanations of the calculation method.

[0073] A limiting case of acceleration is formed by an acceleration difference Δ a Gf,t max / t EM , with which the relative velocity Δ v x ( t SP ) at the time t SP at the end of the lane change or at the time t EM is completely dismantled for the reeving process.

[0074] Depending on the sign of the relative velocity Δ v x ( t SP ) at the time t SP The initial limiting case distance Δ can be determined. x MM,Gf,t max / t EM to calculate the vehicle center point, which would be necessary so that, given a relative speed Δ v x ( t SP ) a final point of approach before the vehicles EGO, PE1 to PE3 would move away from each other again, a touching of the bumpers.

[0075] Is the distance Δ located x MM ( t SP ) the vehicle centers at the time t SP between the limits determined in equation (15) and (16), a differential acceleration is sought for which the bumpers of vehicles EGO, PE1 to PE3 touch (Δ x SS,t = 0), before the vehicles EGO, PE1 to PE3 move away from each other again. This case occurs when: Δ x SS , t = Δ x MM , init t SP ± L + Δ v x t SP t + 1 2 a x , Ego , n − a x , PE t 2 ; t ∈ t EM , t max − t SP Solving for t yields only one solution. This is the case when the square root of the solution for quadratic equations of the form ax 2< + bx + c = 0 results in zero. The calculation for a time of contact of the bumpers Δ x SS , t lies between the point in time t EM of the merging process and the end of the lane change maneuver, and is used for each shift t SP calculated from the start time.

[0076] Depending on the sign of the relative velocity Δ v x ( t SP ) at the time t SP The number of possible cases changes in equations (21) and (22). For a positive relative velocity Δ v x ( t SP ) the maximum longitudinal acceleration a x,PEi,max determined by equation (21a), (21b) or (21c), while the minimum longitudinal acceleration a x,PEi,min is determined only by equation (22d) or (22f). For a negative relative velocity Δ v x ( t SP ) the opposite is true, with the maximum longitudinal acceleration a x,PEi,max then determined by equation (21a) or (21c). Equation (17) for the limiting case position for the minimum longitudinal acceleration. a x,PEi,min at positive relative velocity Δ v x ( t SP ) is obtained by equating equations (22d) and (22f), or equation (18) for the limiting case position for the maximum longitudinal acceleration. a x,PEi,max at negative relative velocity Δ v x ( t SP ) by equating equations (21a) and (21c).

[0077] Figur 10 illustrates the limiting case positions from equations (15) to (18) and individual areas from equations (21a-c) and (22d-f).

[0078] Determined longitudinal acceleration values a x,PE,min and a x,PE,max From equations (21a) to (21c) and (22d) to (22f) the following are then used as the integration limits, as in Figur 8 As shown, the probability of collision is used as a safety measure S1 in the calculation. For this purpose, the probability density function determined at an earlier time is used. pdf integrated. The collision probability is calculated as a function of the displacement. t SP weighted, with the weighting determined by a Figur 8 shown straight line G SP,tSP is defined. In particular, it shows Figur 8 a derivation of the collision probability as a safety measure S1.

[0079] The rationale for the weighting curve is as follows: The later the lane change maneuver begins for the corresponding other vehicles PE1 to PE3, the less time is available to complete the maneuver, thus reducing the risk of a collision. Furthermore, it can be assumed that as the lane change maneuver of vehicle EGO progresses, the probability of lane changes initiated by other vehicles PE1 to PE3 also decreases, since the probability of EGO's movement being perceived by other vehicles PE1 to PE3 increases. The weighted individual collision probabilities are then combined to determine an overall collision probability. P GKol,PEi,n summed up. The total collision probability. P GKol,PEi,n can also be calculated without a weighting line and used as a safety measure S1. P GKol , PE i , n = ∑ t SP = 0 t SP , End ∫ a x , PE i , min t SP a x , PE i , max t SP pdf a x , PE da x , PE ⋅ G SP , t SP

[0080] In an upper area of ​​the Figur 8 Two areas, B1 and B2, are shown with different hatching. The first area, B1, represents possible transverse collisions due to overlapping vehicle surfaces between vehicle EGO and a corresponding further vehicle, PE1 to PE3.

[0081] A lower area B2 represents a possible occurrence of longitudinal collisions between the vehicle EGO and the corresponding further vehicles PE1 to PE3.

[0082] By means of the straight line G SP,tSP Below this is an area A G = 1 = 1 2 G 0 t SP , End Additionally, an intersection point with the abscissa is determined using a last relevant starting time. t SP,End The lane change of the corresponding additional vehicle PE1 to PE3 is defined. This last relevant start time t SP,End represents a point in time at which the corresponding further vehicle PE1 to P3 begins its lane change maneuver and at which there is sufficient time to touch the lane boundary SB of the target lane ZS with the vehicle surface facing the vehicle EGO.

[0083] An intersection point G 0 with the ordinate axis results from a requirement for the area A G = 1 = 1 2 G 0 t SP , End below the straight line G SP,tSP to G 0 = 2 t SP , End A slope m GSP the straight line G SP,tSP is determined as follows: m G SP = − G 0 t SP , End .

[0084] The total collision probability of all PEs is then summed ( AGKol =accumulated GKol, n PE = Number of potential lane mergers). P AGKol , PE , n = ∑ i = 1 n PE P GKol , PE i , n

[0085] The overall collision probability P AGKol,PE,n It can be integrated into any cost function of a trajectory planning to calculate the optimal longitudinal acceleration ax,EGO under a wide variety of requirements and / or constraints regarding engine type, coefficient of friction, comfort requirements, legal regulations, etc. If the calculated acceleration effort of the vehicle EGO, which would be necessary to rule out a potential collision, has a detrimental effect on other requirements, it is also possible to postpone the lane change maneuver until a later time, when the initial conditions for performing a safe lane change have changed.

[0086] Figur 9 shows a representation of a relative longitudinal distance profile of the vehicle bumpers for calculating a minimum distance dx,min between the vehicle EGO and the corresponding further vehicle PE1 to PE3 if no collision occurs between them.

[0087] If no collision occurs, the minimum distance dx,min, also referred to as the minimum longitudinal distance, is used as a further safety measure S2. The minimum distance dx,min is either determined by the shearing moment. t EM or at the moment of maximum lane change duration t max minimal.

[0088] In particular, it shows Figur 9 the relationship between the minimum distance dx,min and the relative longitudinal velocity Δ v x ( t SP = 0) via the lane change maneuver.

[0089] The shift t SP The start time for initiating the lane change maneuver of the corresponding further vehicle PE1 to PE3 is set to zero, since when the two lane change maneuvers start simultaneously, there is the most time available to reduce a relative longitudinal distance.

[0090] The distance between the two facing vehicle bumpers at the merging moment and the time of the maximum lane change duration depends on the most critical acceleration of the corresponding other vehicle PE1 to PE3, depending on the initial situation Δ x MM,init,PEi , Δ v x,init,PEi : Δ a x , data , max , n = a x , Ego , n − a x , PE , data , max ; Δ a x , data , min , n = a x , Ego , n − a x , PE , data , min Δ x SS , t EM , Δ a x , max = Δ x MM , init , PE i − L + Δ v x , init , PE i t EM + Δ a x , data , max , n 2 t EM 2 Δ x SS , t max , Δ a x , max = Δ x MM , init , PE i − L + Δ v x , init , PE i t max + Δ a x , data , max , n 2 t max 2 Δ x SS , t EM , Δ a x , min = Δ x MM , init , PE i + L + Δ v x , init , PE i t EM + Δ a x , data , min , n 2 t EM 2 Δ x SS , t max , Δ a x , min = Δ x MM , init , PE i + L + Δ v x , init , PE i t max + Δ a x , data , min , n 2 t max 2

[0091] Depending on the case distinction, a minimum of the minimum distance dx,min is then obtained from: d x , min , n = min Δ x SS , t EM , Δ a x , min Δ x SS , t max , Δ a x , min , f ü r a x , PE i , max < a x , PE , data , min 0 , f ü r a x , PE , data , min ≤ a x , PE , , min ≤ a x , PE , data , max ∨ a x , PE , data , min ≤ a x , PE i , max ≤ a x , PE , data , max min Δ x SS , t EM , Δ a x , max Δ x SS , t max , Δ a x , max , f ü r a x , PE i , min > a x , PE , data , max

[0092] The procedure enables a safety assessment for an automated driving vehicle, in particular an autonomous driving vehicle EGO.

[0093] By changing the longitudinal acceleration a x,EGO,n The longitudinal accelerations of the vehicle EGO can be a x,PEThe other vehicles PE1 to PE3, which would be necessary for a collision and are therefore potentially merging into the lane, are shifted so that they are outside a critical area determined using real-world driving data. Vehicle EGO is thus able to reduce the risk of a collision even before a lane change maneuver into the middle lane F2, or to deliberately postpone the start of the lane change maneuver, thereby increasing the safety of vehicle EGO and the other vehicles PE1 to PE3.

Claims

1. Method for the safety evaluation of a lane change maneuver in the automated driving mode of a vehicle (EGO) comprising environment sensors, the environment of the vehicle (EGO) and objects located in the environment being detected on the basis of captured signals from the environment sensors, a collision risk being determined by means of hypothetical lane change maneuvers of other vehicles (PE1 to PE3) in the right lane (F3) or the left lane (F1) prior to an initiated lane change maneuver of the vehicle (EGO) from a left lane (F1) to a middle lane (F2) or from a right lane (F3) to the middle lane (F2) of a multi-lane roadway portion (F), characterized in that - longitudinal accelerations (ax,PE) of the other vehicles (PE1 to PE3) are determined on the basis of a maximum lane change duration and a cutting-in torque (tEM), which longitudinal accelerations lead to a collision due to vehicle surfaces of the vehicle (EGO) and the other vehicles (PE1 to PE3) overlapping, and - an execution of the lane change maneuver is evaluated, on the basis of a collision probability as a safety measure (S1) and a minimum distance (dx,min) in the event of a collision non-occurrence as a further safety measure (S2), as a function of a longitudinal position (ΔxMM,init,PEi) of the vehicle (EGO) relative to the other vehicles (PE1 to PE3) and initial longitudinal speeds (Δvx,init,PEi) of the vehicle (EGO) relative to the other vehicles (PE1 to PE3) at the start of the lane change maneuver.

2. Method according to claim 1, characterized in that the two safety measures (S1, S2) are determined using a model-based approach and the collision probability and the minimum distance (dx,min) during an executed lane change maneuver are influenced by changing the longitudinal acceleration (ax,EGO,n) and / or the initial situation (ΔxMM,init,PEi,Δvx,init,PEi) of the vehicle (EGO) with respect to a nearest moving vehicle (PE1 to PE3).

3. Method according to claim 1 or claim 2, characterized in that the collision probability is determined as a safety measure (S1) on the basis of a previously determined probability of longitudinal accelerations (ax,PE) which can be expected of the other vehicles (PE1 to PE3), on the basis of an initial situation (ΔxMM,init,PEi, Δvx,init,PEi), on the basis of geometric vehicle information (lEGO) of the vehicle (EGO) and geometric vehicle information (lPEi) of the other vehicles (PE1 to PE3), on the basis of start times of the hypothetical lane change maneuvers of the other vehicles (PE1 to PE3), a duration of the lane change maneuver and a planned longitudinal acceleration (ax,EGO,n) of the vehicle (EGO).

4. Method according to any of the preceding claims, characterized in that the minimum distance (dx,min) as a further safety measure (S2) is evaluated on the basis of a minimum longitudinal distance between a bumper of the vehicle (EGO) and a bumper of the nearest moving other vehicle (PE1 to PE3), the minimum distance (dx,min) being chosen during the lane change maneuver after it has been determined that lateral coordinates of the vehicles (EGO, PE1 to PE3) intersect.