Procedure for the safety assessment of a lane change maneuver in automated driving of a vehicle

Abstract

Method for the safety assessment of a lane change maneuver in the automated driving mode of a vehicle (EGO) with an environmental sensor system, wherein an environment of the vehicle (EGO) and objects located therein are detected based on signals recorded by the environmental sensor system, wherein - before 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 road section (F), a collision risk is determined by means of hypothetical lane change maneuvers of other vehicles (PE1 to PE3) in the right lane (F3) or the left lane (F1), - based on a maximum lane change duration and a cutting-in moment (t EM ) Longitudinal accelerations (a x,PE) of the other vehicles (PE1 to PE3) are determined, which lead to a collision due to an overlap of the vehicle surfaces of the vehicle (EGO) and the other vehicles (PE1 to PE3), - carrying out the lane change maneuver depending on a relative longitudinal position (Δx MM,init,PE i ) of the vehicle (EGO) to the other vehicles (PE1 to PE3) and initial relative longitudinal velocities (Δv x,init,PE i ) of the vehicle (EGO) to the other vehicles (PE1 to PE3) at the start of a lane change maneuver based on a collision probability (P Kollision ) as a safety measure (S1) and a minimum distance (d x,min ) is assessed as an additional safety measure (S2) if a collision does not occur, - when determining the collision probability (P Kollision ) a height of a jerk (j) a longitudinal acceleration (a x,PE ) of the other vehicles (PE1 to PE3) is taken into account and - the longitudinal acceleration (a x,EGO ) of the vehicle (EGO) is optimized in such a way that a minimum longitudinal acceleration (a x,PE,min ) and a maximum longitudinal acceleration (a x,PE,max ) of the other vehicles (PE1 to PE3) require a longitudinal acceleration change effort, which in each case results in a statistically low collision probability (P Kollision ), characterized in that the collision probability (P Kollision ) as a safety measure (S1) based on a previously determined probability of expected longitudinal accelerations (a x,PE ) of the other vehicles (PE1 to PE3), based on a Initial situation (Δx MM,init,PE i , Δv x,init,PE i), based on geometric vehicle information of the vehicle (EGO) and geometric vehicle information of the other vehicles (PE1 to PE3), based on starting 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 (a x,EGO,n ) of the vehicle (EGO) is determined.

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 an environmental sensor system, wherein an environment of the vehicle and objects located therein are detected on the basis of signals recorded by the environmental sensor system.

[0002] US Pat. No. 8,244,408 B2 discloses a method for assessing a risk associated with the driving 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. Each of several objects located in the vicinity of the vehicle is monitored. The locations of each of the objects are predicted relative to a projected trajectory of the vehicle, and a collision risk level between the vehicle and each of the objects is assessed.

[0003] Furthermore, EP 3 281 831 A1 describes a control system and a control method for determining a probability of a lane change by a preceding motor vehicle. The control system is configured to detect another motor vehicle participating in traffic in front of the own motor vehicle using the at least one environment sensor, to determine a lateral movement of the other motor vehicle relative to a lane in which the other motor vehicle or the own motor vehicle is located, and to calculate a movement-based probability of a lane change by the other motor vehicle based on the determined lateral movement of the other motor vehicle.Furthermore, the control system is configured and intended to determine a current traffic situation based on the environmental data obtained by means of the environmental sensor, to calculate a traffic situation-based probability for a lane change of the other motor vehicle based on the determined current traffic situation, and to calculate an overall probability for a lane change of the other motor vehicle based on the movement-based probability and the traffic situation-based probability.

[0004] Furthermore, US 2010 / 0 228 419 A1 discloses a method for assessing a collision risk in connection with the operation of a vehicle, wherein the vehicle is configured to perform an autonomous lane change maneuver. The method comprises the following steps: - Monitoring each of a plurality of object vehicles located in the vicinity of the vehicle; - predicting the locations of each of the object vehicles relative to a projected trajectory of the vehicle in future time steps; and - Assessing a collision risk level between the vehicle and each of the object vehicles in the future time steps.

[0005] DE 10 2019 129 879 A1 describes a method for the automated control of a motor vehicle traveling on a road in a current lane, the road having another lane. The method comprises the following steps: - generating and receiving two preliminary driving maneuvers comprising a change from the current lane to the further lane and a start time of the change, the start times of the two preliminary driving maneuvers being at different times; - comparing the two driving maneuvers, taking into account the respective starting times; and - Select one of the start times based on the comparison.

[0006] Furthermore, DE 196 47 430 A1 describes a method for automatically braking a passenger-driven motor vehicle, in which a relative speed to an obstacle located approximately in front of the vehicle in the direction of travel is determined. In addition, a distance between the vehicle and the obstacle is determined, and the determined distance is compared with a braking distance of the vehicle at a speed approximately corresponding to the relative speed. Depending on the comparison result, an automatic braking process is performed if the determined distance is shorter than the braking distance.

[0007] The invention is based on the object of providing a novel method for the safety assessment of a lane change maneuver in the autonomous driving operation of a vehicle.

[0008] The object is achieved according to the invention by a method which has the features specified in claim 1.

[0009] Advantageous embodiments of the invention are the subject of the subclaims.

[0010] A method for the safety assessment of a lane change maneuver in autonomous driving of a vehicle with an environmental sensor system, whereby an environment of the vehicle and objects located therein are detected based on signals recorded by the environmental sensor system, provides that - before a lane change maneuver of the vehicle from a left lane to a middle lane or from a right lane to a middle lane of a multi-lane road section is initiated, a collision risk is determined by means of hypothetical lane change maneuvers of other vehicles in the right lane or the left lane, whereby - based on a maximum lane change duration and a cutting-in moment, longitudinal accelerations are calculated that 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 assessed depending on the relative longitudinal position of the vehicle to the other vehicles and the relative longitudinal speeds of the vehicle to the other vehicles at the start of a lane change maneuver using a collision probability as a safety measure and a minimum distance in the event of no collision as a further safety measure, and - when determining the probability of collision, the magnitude of a jerk of a longitudinal acceleration of the other vehicles is taken into account, whereby - the longitudinal acceleration of the vehicle is optimized in such a way that a minimum longitudinal acceleration and a maximum longitudinal acceleration of the other vehicles require a longitudinal acceleration change effort which in each case has a statistically low collision probability.

[0011] According to the invention, the collision probability is calculated as a safety measure based on - a previously determined probability of expected longitudinal accelerations of the other vehicles, - an initial situation, - geometric vehicle information of the vehicle and geometric vehicle information of the other vehicles, - starting times of the hypothetical lane change maneuvers of the other vehicles, - a duration of the lane change maneuver and - a planned longitudinal acceleration of the vehicle.

[0012] In particular, the method provides for a check, even before the vehicle begins to change lanes, to determine whether a lane change can still be performed safely, even if the vehicle misjudges the lane change maneuver in relation to other vehicles, or if a lane change cannot be predicted from a given context. For this reason, the collision probability is determined solely based on longitudinal dynamics, since it is not possible to predict whether other vehicles will change lanes. Longitudinal dynamics refers to both longitudinal acceleration and jerk.

[0013] By applying the method, longitudinal acceleration optimizations of the automated vehicle are designed on the basis of an actual, in particular measured, initial longitudinal acceleration of a potential additional vehicle merging into the lane of the automated vehicle in such a way that the longitudinal acceleration of the potential merging vehicles requires a longitudinal acceleration change effort that has a statistically low probability of occurrence, so that the collision probability is reduced.

[0014] Jerk is defined as the instantaneous rate of change of a body's acceleration over time. Especially in an electric vehicle, a change in acceleration results in a longitudinal jerk.

[0015] In particular, the application of the procedure can be used to assess / quantify a collision risk of a vehicle at the tactical level for performing a lane change maneuver into the middle lane.

[0016] A vehicle system for automated, in particular autonomous, driving can reduce the risk of collision before the lane change maneuver by adapting its target behavior or postpone the start of the lane change maneuver if both a positive and a negative acceleration effort is too high for the vehicle and / or until the initial situation for a safe lane change has improved.

[0017] Embodiments of the invention are explained in more detail below with reference to drawings.

[0018] Showing: Fig. 1 schematically shows a road section with three lanes and two vehicles, Fig. 2 schematically shows two images of the road section with one and the same initial situation and changed longitudinal acceleration, Fig. 3 schematically a derivation of the sheering moment in a specific situation Fig. 4 schematically shows a derivation of the sheering moment in another specific situation, Fig. 5 schematically shows a derivation of the sheering moment in another specific situation, Fig. 6 schematically shows a derivation of the sheering moment in another specific situation, Fig. 7 schematically shows a representation of starting position limit cases and their relative longitudinal velocity curves, Fig. 8 schematically shows a derivation of a collision probability as a safety measure, Fig. 9 schematically shows a calculation of a minimum distance between the vehicle and a next vehicle in a lane after the next as a further safety measure, Fig. 10 schematic representation of different limiting cases for the calculation of longitudinal acceleration limits, Fig. 11A schematically shows a diagram with a collision probability density without taking a jerk into account, Fig. 11B schematically shows another diagram with shifted collision probability density by adjusting a longitudinal acceleration of the vehicle, Fig. 12A schematically shows a diagram with a collision probability density and longitudinal acceleration limits, Fig. 12B schematically shows a diagrammatic calculation of the longitudinal acceleration differences used to calculate jerk limits and Fig. 12C schematically shows a diagram taking into account the probability of occurrence of a jerk of a longitudinal acceleration.

[0019] Corresponding parts are provided with the same reference numerals in all figures.

[0020] Fig. Figure 1 shows a road section F with three lanes F1 to F3 running in the same direction. A vehicle EGO is traveling in autonomous mode in a left lane F1 and intends to perform a lane change maneuver into a center lane F2. A lane change trajectory T1 of the vehicle EGO from the left lane F1 to the center lane F2 is shown.

[0021] Another vehicle PE1 is traveling in a right-hand lane F3, which may possibly, i.e., even without a recognizable intention, intend to perform a lane change maneuver into the center lane F2. A hypothetical lane change trajectory T2 of the other vehicle PE1 from the right-hand lane F3 to the center 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 in Fig. 1 shown.

[0022] For automated, especially autonomous, driving of an EGO vehicle, a lane change represents a comparatively complex driving maneuver. This requires planning and implementing longitudinal and lateral movements of the EGO vehicle, taking into account the surrounding situation.

[0023] According to Donges and Michon, it is known that an evaluation of a lane change maneuver takes place on three levels: strategic, tactical, and operational. The following problem description refers in particular to the tactical level, which describes the attractiveness and feasibility of a lane change maneuver. Typically, an autonomous lane change at this level is only analyzed by including object information, which, according to the present embodiment, is Fig. 1 are assigned to the left lane F1 and a target lane ZS, i.e., the middle lane F2. Object information of other vehicles PE1 to PE3, which are shown in the following figures, in the next but one lane, i.e., the right lane F3, is not taken into account or is only taken into account indirectly, for example via potential fields, if a predicted behavior is not relevant for the target lane ZS. The number of other vehicles PE1 to PE3 is not fixed at 3 and can vary. Incorrect predictions or lane changes that are not apparent from a context are therefore not taken into account or are only taken into account via generic fallback trajectories.However, 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 center lane F2, it may happen that another vehicle PE1 to PE3 decides to change to the same destination lane ZS during the same period, even without any discernible intention. Such a case represents a comparatively critical situation.

[0024] During lane-changing maneuvers, there is therefore a risk of collision with other vehicles PE1 to PE3 that could change into the middle lane F2 during the same period.

[0025] While a human driver of the EGO vehicle, based on his previous experience, can predict the behavior of surrounding traffic during lane change maneuvers, also taking into account objects, i.e. road users, on a lane after the next but one, in relation to Fig. 1 in the right lane F3 in order to then evaluate its tactical driving decision in terms of attractiveness and feasibility, automated vehicle systems rely on rule sets that evaluate planned tactical behavior based on measurement data from environmental sensors.

[0026] 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.

[0027] In order to tactically evaluate a lane change maneuver into the center lane (F2) while considering object information in the next lane (i.e., the right lane F3), it is necessary to define metrics and parameters that allow quantifying the collision risk with these objects during lane change maneuvers. Based on these, a desired target behavior for the automated driving system can then be derived.

[0028] The following describes a method for the safety assessment of a lane change maneuver in autonomous driving mode of the EGO vehicle with an environmental sensor system, whereby the environment of the EGO vehicle and objects located therein are detected based on signals recorded by the environmental sensors.

[0029] To carry out the procedure, it is assumed that lane change maneuvers of other vehicles PE1 to PE3 cannot be predicted.

[0030] In Fig. 2 are two figures A1, A2 with a road section F and the same initial situation Δx MM,init,PEi Δv x,init,PEi shown, with vehicle EGO traveling in the left lane F1 and intending to perform a lane change maneuver into the center lane F2. Three other vehicles PE1 to PE3 are traveling in the right lane F3.

[0031] A lane change maneuver by vehicle EGO into the center lane F2 is tested for collision risk using hypothetical lane change maneuvers by the other vehicles PE1 to PE3. These vehicles can be either passenger cars or trucks. This means that each of the other vehicles PE1 to PE3 represents a potential lane changer for vehicle EGO. The other vehicles PE1 to PE3 can also be other modes of transport, such as motorcycles. Here, acceleration ranges are determined, and the same principle is applied to the risk analysis for a lane change by vehicle EGO.

[0032] To check the lane change maneuver based on the hypothetical lane change maneuvers of the other vehicles PE1 to PE3, longitudinal accelerations a are determined using linearized cross-sectional profiles, in particular based on a maximum lane change duration and a cutting-in moment.x,PE calculated, which lead to a collision due to an overlap of vehicle surfaces between the vehicle EGO and one of the other vehicles PE1 to PE3. For this purpose, it is defined that the probability of occurrence of the respective longitudinal accelerations a x,PE that lead to a collision, at the same time a collision probability P Kollision describes the collision probability P Kollision corresponds, since the longitudinal acceleration a x,PE is directly related to an overlap of the vehicle surfaces and thus a collision.

[0033] An evaluation of the lane change maneuver at the tactical level is carried out depending on a relative longitudinal position Δx MM,init,PEi , also referred to as initial distance between vehicle centers, as vehicle measurement variable 1 and an initial relative longitudinal speed Δv x,init,PEias vehicle measurement variable 2 at the start of the lane change maneuver using two safety measures S1, S2.

[0034] This results in the relative longitudinal position Δx MM,init,PEi as follows: ΔxMM,init,PEi=xM,EGO,init−xM,PEi,init

[0035] The initial relative longitudinal velocity Δv x,init,PEi is calculated as follows: Δvx,init,PEi=vx,EGO,init−vx,PEi,init

[0036] In particular, an initial longitudinal distance is negative if the vehicle EGO is traveling behind another vehicle PE1 to PE3. The situation is similar for a relative speed Δv x(tSP ), which is positive if the vehicle EGO has a higher longitudinal speed v x,EG0,init than another vehicle PE1 to PE3.

[0037] A safety measure S1 represents the collision probability P Kollision and a further safety measure S2 provides, provided there is no risk of collision, a minimum distance dx,min between the vehicle EGO and the other vehicles PE1 to PE3.

[0038] An assessment of the collision probability P Kollision as a safety measure S1 is based on a collision probability P Kollision , which results from a previously determined probability of expected longitudinal accelerations a x,PE of the other vehicles PE1 to PE3, based on the initial situation 6 XMM,init,PEi , Δv x,init,PEi , based on geometric vehicle information l EGO of the vehicle EGO, a geometric vehicle information l PE of 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 a x,EGO,n of the vehicle EGO.

[0039] An assessment of the minimum distance d x,minAs a further safety measure S2, the minimum longitudinal distance between the bumpers closest to each other is determined. The minimum distance d x,min selected during the entire lane change maneuver after transverse coordinates between the vehicle EGO and at least one other vehicle PE1 to PE3 intersect.

[0040] The two safety measures S1 and S2 are calculated using a model-based method.

[0041] By changing the longitudinal acceleration a x,EGO,n , represented by the index n, and / or a lane change duration, the vehicle EGO can calculate the collision probability P Kollision and the minimum distance d x,min during the lane change maneuver.

[0042] In a first figure A1, a scenario with three other vehicles PE1 to PE3 as potential mergers into the middle lane F2 is shown in their respective initial situation Δx MM,init,PEi , Δv x,init,PEishown.

[0043] A total collision probability P GKol,PEi,n > 0 of the vehicle EGO exists for the vehicle EGO with another first vehicle PE1, where in the first figure A1 a minimum distance d x,min to the respective other vehicle PE1 to PE3 at a longitudinal acceleration a ,x,EGO,0 which, with a total collision probability P GKol,PEi,n > 0 is set to zero.

[0044] In a second figure A2 in Fig. 2 is the same initial situation Δx MM,init,PEi , Δv x,init,PEi as shown in the first figure A1. The vehicle EGO exhibits a changed longitudinal acceleration a x,EGO,n so that new values for the respective collision probability P Kollision and the respective minimum distance d x,min result.

[0045] The EGO vehicle is therefore able to reduce the risk of a collision even before the lane change maneuver is initiated or to deliberately postpone the start of the lane change maneuver if the positive or negative acceleration effort of the EGO vehicle is too high and / or until the initial situation for a safe lane change has improved.

[0046] To implement the procedure, a definition of a start time and an end time of the lane change maneuver is required to distinguish each scenario from other scenarios. 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-end traffic participants for highly automated lane changes. Transforming Mobility - What Next? - Proceedings of the 13th Science Forum on Mobility: Springer Fachmedien Wiesbaden, 2021.

[0047] Using a defined start and end time of a lane change maneuver, averaged longitudinal accelerations are determined based on the recorded measurement data as a function of a lane change direction, in particular with regard to a faster / slower lane F1 to F3, and a vehicle class, from a real-world driving dataset with which lane change maneuvers are performed. In addition, the probability of an averaged longitudinal acceleration with which the lane change maneuver is performed is also determined. A probability density function pdf is created using a frequency distribution as a function of the lane change direction and vehicle class, the integral of which describes the probability of a corresponding acceleration range. The probability density function pdf is then applied to the other vehicles PE1 to PE3 as a function of the lane change direction and their vehicle class.

[0048] Based on the measurement data, a lane change duration t is calculated using the start and end times. PE (Δy ZM ) depending on a distance Δy T, ZM of a vehicle PE1 to PE3 to a target lane center ZM, a lane change direction, particularly with respect to a faster / slower lane F1 to F3, and a vehicle class. The lane change duration t PE (Δy ZM ) is determined over several lane change maneuvers that have a similar distance Δy PE, ZM to the target lane center ZM, determined by averaging.

[0049] Using the determined longitudinal acceleration, a model is developed by which the collision probability P Kollision as safety measure S1 and the minimum distance d x,min between the vehicle EGO and the other vehicles PE1 to PE3 as a further safety measure S2 based on a respective initial situation Δx MM,init,PEi , Δv x,init,PEican be determined, in particular can be calculated, and which influence the vehicle EGO can have by changing its longitudinal acceleration a x,EGO,n taken into account.

[0050] Longitudinal acceleration ranges and their probability are used to calculate the collision probability P Kollision used as safety measure S1. This checks which longitudinal accelerations a x,PE of the respective other vehicle PE1 to PE3 lead to a collision with the vehicle EGO during a lane change maneuver into the middle lane F2.

[0051] Lane change maneuvers of the vehicle EGO are based on the initial situation Δx MM,init,PEi , Δv x,init,PEi to one or more other vehicles PE1 to PE3 in the right lane F3. This evaluation is based on an initial distance Δx MM,init,PEi of the two vehicle centers and an initial relative longitudinal velocity Δv x,init,PEiThese two parameters are recorded using signals from the environmental sensors of the automated, particularly autonomous, vehicle EGO.

[0052] Based on the initial situation Δx MM,init,PEi , Δv x,init,PEi a minimum longitudinal acceleration a x,PE,min and a maximum longitudinal acceleration a x,PE,max of the other vehicles PE1 to PE3 are determined, for which a collision just barely occurs during a lane change maneuver, given a linearized cross-sectional profile of the vehicle EGO and the other vehicles PE1 to PE3. Values within these longitudinal acceleration limits, including the limit values, also lead to a collision.

[0053] A necessary longitudinal acceleration range a x,PE,min to a x,PE,max of the other vehicle PE1 to PE3, which leads to a potential collision, can be caused by the longitudinal acceleration a x,EGObe influenced, whereby different longitudinal accelerations a x,EGO,n represented by the index n.

[0054] A period to be considered is defined by a maximum of the lane change duration t Ego of the vehicle EGO and the other vehicles PE1 to PE3 t max = max(t PE (Δy ZM ), t Ego ) is defined.

[0055] In particular, this is because a longer lane change duration provides more time to achieve a higher initial relative longitudinal speed Δv 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, whereby this represents a more critical case. Such a case is described further below. In addition, the beginning of the period to be considered, within which a collision can occur, is defined by a time t EM a reeving process is defined.

[0056] At time t EM To determine the point in time at which the two vehicle surfaces laterally intersect for the first time, the transverse movements of the vehicle EGO and the corresponding other vehicle PE1 to PE3 are linearized. Fig. 3 to 6 each illustrate a calculation rule and show four possible cases.

[0057] Assuming a constant lateral speed, the initial distance Δy PE,ZM to the target lane center ZM four possible times t EM for a reeving operation. Case 1:

[0058] One in Fig. The embodiment shown in Figure 3 shows possible intersection points of resulting straight lines, which represent the linearized transverse movement of the vehicle sides facing the vehicle (ZF).

[0059] If the two vehicle surfaces overlap before the completion of one of the two lane change maneuvers, the following applies: tEM=|yZF,Ego(tSP)−yZF,PE,init||vy,Ego+vy,PE|

[0060] Condition: (tEGO=|yZF,Ego,End−yZF,Ego(tSP)||vy,Ego|≥tPE,FPC=|yZF,Ego,End−yZF,PE,init||vy,PE|)∧ (tPE(∇yZM)=|yZF,PE,End−yZF,PE,init||vy,PE|+tSP>tEGO,FPC=|yZF,Ego,init−yZF,Pe,End||vy,Ego|) t SP This describes a shift in the lane change start of the corresponding additional vehicle PE1 to PE3. Assuming that there are lane change maneuvers that cannot be recognized in context, the corresponding additional vehicle PE1 to PE3 can decide to also change into lane F1 to F3 at any possible point in time during the lane change maneuver of the vehicle EGO.

[0061] By shifting t SPIf the lane change start of the corresponding other vehicle PE1 to PE3 is set to a later point in time, the period to be considered is shortened.

[0062] An initial position and relative velocity are calculated as follows: ΔxMM(tSP)=ΔxMM,init,PEi+Δvx,init,PEitSP+12(ax,Ego,n−ax,PEi,init)tSP2 Δvx(tSP)=Δvx,init,PEi+(a,Ego,n−ax,PEi,init)tSP

[0063] It is assumed that the initial longitudinal acceleration a x,PEi,init of other vehicles PE1 to PE3 cannot be measured exactly or only inaccurately and is assumed to be zero for the procedure described here. yZF,Ego(tSP)=yZF,EGO,init+vy,EGOtSP tSP∈[0,tmax−|ySB,PE+−yZF,PE,init||vy,PE|]

[0064] A first possible contact between the vehicle EGO and the corresponding other vehicle PE1 to PE3 is in Fig. 3 also shown labeled. Case 2:

[0065] If the corresponding further vehicle PE1 to PE3 reaches a lateral end position of the vehicle EGO after the vehicle EGO has finished its lateral movement, but before the end of the considered period (t max - t SP ), then: tEM=|yZF,Ego,End−yZF,PE,init||vy,PE|

[0066] Condition: (tPE(ΔyZM)>tEgo)∧(tmax−tSP≥tPE,FPC=|yZF,Ego,End−yZF,Pe,init||vy,PE|)≥tEGO=|yZF,Ego,End−yZF,Ego(tSP)||vy,Ego| as in the example in Fig. 4 is shown. Case 3:

[0067] If the corresponding additional vehicle PE1 to PE3 reaches the lateral end position only after the end of the considered period (t max - t SP ), but reached within the period under consideration (t max - t SP ) nor the lane boundary (y SB,PE ) of the target track ZS, then: tEM=tmax−tSP

[0068] Condition: tPE,FPC=|yZF,Ego,End−yZF,PE,init||vy,PE|>tmax−tSP≥tPE,SB=|ySN,PE−yZF,PE,init||vy,PE|.

[0069] 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 therefore counted as an overlap. Case 4:

[0070] If the corresponding additional vehicle PE1 to PE3 reaches its lateral end position y ZF,PE,end before the vehicle EGO reaches a lateral end position y ZF,EGO,end of the corresponding additional vehicle PE1 to PE3, the following applies: tEM=|yZF,Ego(tSP)−yZF,Ego,End||vy,Ego|

[0071] Condition: tEGO,FPC−tSP=|yZF,PE,init−yZF,Ego,End||vy,EGO|−tSP≥tPE(ΔyZM)=|yZF,Ego,End−yZF,PE,init||vy,PE|

[0072] Case 4 is completed with equation (13).

[0073] The following calculation rule is used to determine a minimum longitudinal acceleration 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 Δx MM,init,PEi Δv x,init,PEi to a collision:

[0074] Acceleration difference limiting cases: ΔaGf,tmax=−Δvx(tSP)Tmax−tSP;Δalimiting case,tEM=−Δvx(tSP)tEM

[0075] Starting position limiting cases (Gf): ΔxMM,Gf,tEM={12ΔaGf,tmax(tmax−tSP)2−Lfor Δvx(tSP)≥012ΔaGf,tmax(tmax−tSP)2+Lfor Δvx(tSP)<0; ΔxMM,Gf,tEM={12ΔaGf,tmaxtEM2−Lfor Δvx(tSP)≥012ΔaGf,tmaxtEM2+Lfor Δvx(tSP)<0 ΔxMM,amin,equal=−Δvx(tSP)tEM1+tEMtmax−tSP+L for Δvx(tSP)≥0; ΔxMM,amax,equal=−Δvx(tSP)tEM1+tEMtmax−tSP−L for Δvx(tSP)<0 with: L=lEGO+lPEi2; l ECO = vehicle length EGO, lPEi = Vehicle length PE1 to PE3 ΔxMM,tmax=ΔxMM(tSP)+Δvx(tSP)(tmax−tSP)+12ax,Ego,n(tmax−tSP)2; ΔxMM,tEM=ΔxMM(tSP)+Δvx(tSP)tEM+12ax,Ego,ntEM2 ax,PEi,max={ 2(ΔxMM,tmax+L)(tmax−tSP)2ax,Ego,n−12Δvx2(tSP)ΔxMM(tSP)+L 2(ΔxMM,tEM+L)tEM2for(ΔxMM(tSP)<ΔxMM,Gf,tmax∧Δvx(tSP)≥0)∨(ΔxMM(tSP)≤ΔxMM,amax,equal∧Δvx(tSP)<0)for ΔxMM,Gf,tmax≤ΔxMM(tSP) ≤ ΔxMM,Gf,tEM ∧Δvx(tSP)≥0for ΔxMM,Gf,tEM<ΔxMM(tSP)∧Δvx(tSP)≥0)∨(ΔxMM,amax,equal<ΔxMM(tSP)∧Δvx(tSP)<0) ax,PEi,min={ 2(ΔxMM,tmax−L)(tmax−tSP)2ax,Ego,n−12Δvx2(tSP)ΔxMM(tSP)−L 2(ΔxMM,tEM−L)tEM2for(ΔxMM,Gf,tmax≤ΔxMM(tSP)∧Δvx(tSP)<0)∨(ΔxMM,amin,equal≤ΔxMM(tSP)∧Δvx(tSP)≥0)for ΔxMM,Gf,tEM≤ΔxMM(tSP) ≤ ΔxMM,Gf,tmax ∧Δvx(tSP)<0for (ΔxMM(tSP)<ΔxMM,Gf,tEM∧Δvx(tSP)<0)∨(ΔxMM(tSP)<ΔxMM,amin,equal∧Δvx(tSP)≥0) Fig. 7 shows explanations of the calculation rule.

[0076] An acceleration limit case is an acceleration difference Δa Gf,tmax / tEM, with which the relative velocity Δv x (t SP ) at time t SP to the end of the lane change or at time t EM is completely dismantled for the reeving process.

[0077] Depending on the sign of the relative velocity Δv x (t SP ) at time t SP the initial limiting distance Δx MM,Gf,tmax / tEM of the vehicle centers, which would be necessary so that at a given relative speed Δv x (t SP ) a last point of approach before the vehicles EGO, PE1 to PE3 would move away from each other again is a touch of the bumpers.

[0078] If the distance Δx MM (t SP ) of the vehicle centers at time t SPbetween the limits determined in equations (15) and (16), a differential acceleration is sought for which the bumpers of the vehicles EGO, PE1 to PE3 touch (Δx SS,t = 0) before the vehicles EGO, PE1 to PE3 move away from each other again. This case occurs when: ΔxSS,t=ΔxMM,init(tSP)±L+Δvx(tSP)t+12(ax,Ego,n−ax,PE)t2;t∈tEM,(tmax−tSP) 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 Δx SS,t lies between the time t EM of the merging process and an end of the lane change maneuver and is calculated for each shift t SP of the start time.

[0079] Depending on the sign of the relative velocity Δv x (t SP ) at time tSP the number of possible cases in equations (21) and (22) changes. For positive relative velocity Δv 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 Δv x (c SP ) the situation is reversed, with the maximum longitudinal acceleration a x,PEi,max is then determined by equation (21a) or (21c). Equation (17) for the limiting position for the minimum longitudinal acceleration a x,PEi,min at positive relative velocity Δv 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 Δv x (t SP) by equating equations (21a) and (21c).

[0080] Fig. Figure 10 illustrates the limiting case positions from equations (15) to (18) and individual regions from equations (21a-c) and (22d-f).

[0081] Determined longitudinal acceleration values a x,PE,min and a x,PE,max from equations (21a) to (21c) and (22d) to (22f) are then used as integral limits, as in Fig. 8, when calculating the collision probability P Kollision used as a safety measure S1. For this purpose, the probability density function pdf determined at an earlier time is integrated. The collision probability P Kollision is dependent on the displacement t SP weighted, whereby the weighting is determined by Fig. 8 shown straight line G SP ,t SP is defined. In particular, Fig. 8 a derivation of the collision probability P Kollisionas safety measure S1.

[0082] The reason for the weighting line is: The later the lane change maneuver begins for the corresponding additional vehicle PE1 to PE3, the less time is available to complete the lane change maneuver, thereby reducing the risk of a collision. Furthermore, it can be assumed that as the lane change maneuver of vehicle EGO progresses, the probability that a lane change will be initiated by additional vehicles PE1 to PE3 also decreases, since the probability with which the movement of vehicle EGO is perceived by additional vehicles PE1 to PE3 increases. The weighted individual collision probabilities are then combined to form an overall collision probability P GKol,PEi,n summed. The total collision probability P GKol,PEi,n can also be calculated without a weighting line and used as a safety measure S1. PGKol,PEi,n=∑tSP=0tSP,End∫ax,PEi,max(tSP)ax,PEi,min(tSP)pdf(ax,PE)dax,PE⋅GSP,tSP

[0083] In an upper area of the Fig. 8, two areas B1 and B2 are shown with different hatching. A first area B1 represents possible transverse collisions due to overlapping vehicle surfaces between the vehicle EGO and a corresponding other vehicle PE1 to PE3.

[0084] A lower area B2 represents a possible occurrence of longitudinal collisions between the vehicle EGO and the corresponding other vehicle PE1 to PE3.

[0085] Using the straight line G SP,tSP there is an area below this AG=1=12G0tSP,End In addition, an intersection point with the abscissa is determined using a last relevant starting time t SP,End for the lane change of the corresponding additional vehicle PE1 to PE3. This last relevant start time t SP,Endrepresents a point in time at which the corresponding further vehicle PE1 to P3 begins its lane change maneuver and at which time is sufficient to touch the lane boundary SB of the target lane ZS with the vehicle surface facing the vehicle EGO.

[0086] An intersection point G0 with the ordinate axis results from a requirement for the area AG=1=12G0tSP,End below the straight line G SP,tSP to G0=2tSP,End A gradient of m GSP the straight line G SP,tSP is determined as follows: mGSP=−G0tSP,End.

[0087] The total collision probability of all PEs is then summed (AGKol = accumulated GKol, n PE = number of potential cut-ins). PAGKol,PE,n=∑i=1nPEPGKol,PEi,n

[0088] The total collision probability P AGKol,PE,ncan be integrated into any cost function of a trajectory planning to determine the optimal longitudinal acceleration a x,EGO under a wide variety of requirements and / or restrictions with regard to engine size, coefficient of friction, comfort requirements, legal requirements, etc. If the calculated acceleration effort of the vehicle EGO, which would be necessary to rule out a potential collision, has too great an adverse effect on other requirements, it is also possible to carry out the lane change maneuver at a later time when the initial situation for carrying out a safe lane change maneuver has changed.

[0089] Fig. 9 shows a representation of a relative longitudinal distance of the vehicle bumpers for calculating a minimum distance d x,min between the vehicle EGO and the corresponding other vehicle PE1 to PE3, if no collision occurs between them.

[0090] If there is no collision, the minimum distance d x,min , also known as the minimum longitudinal distance, is used as an additional safety measure S2. The minimum distance d x,min either at the reeving moment t EM or at the moment of maximum lane change duration t max minimal.

[0091] In particular, Fig. 9 the relationship of the minimum distance d x,min and the relative longitudinal velocity Δv x (t SP = 0) about the lane change maneuver.

[0092] The shift t SP The starting time for initiating the lane change maneuver of the corresponding additional vehicle PE1 to PE3 is set to zero, since when the two lane change maneuvers start simultaneously, most of the time is available to reduce a relative longitudinal distance.

[0093] The distance between the two facing vehicle bumpers at the moment of merging 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 Δx MM,init,PEi Δv x,init,PEi : Δax,data,max,n=ax,Ego,n−ax,PE,data,max;Δax,data,min,n=ax,Ego,n−ax,PE,data,min ΔxSS,tEM,Δax,max=ΔxMM,init,PEi−L+Δvx,init,PEitEM+Δax,data,max,n2tEM2 ΔxSS,tmax,Δax,max=ΔxMM,init,PEi−L+Δvx,init,PEitmax+Δax,data,max,n2tmax2 ΔxSS,tEM,Δax,min=ΔxMM,init,PEi+L+Δvx,init,PEitEM+Δax,data,min,n2tEM2 ΔxSS,tmax,Δax,min=ΔxMM,init,PEi+L+Δvx,init,PEitmax+Δax,data,min,n2tmax2

[0094] A minimum of the minimum distance d x,min Depending on the case, the result is then: dx,min,n={min(|ΔxSS,tEM,Δax,min|,|ΔxSS,tmax,Δax,min|),for ax,PEI,max <ax,PE,data,min 0, fu¨r ax,PE,data,min≤ax,PE,,min≤ax,PE,data,max ∨ ax,PE,data,min≤ax,PEt,max≤ax,PE,data,maxmin(|ΔxSS,tEM,Δax,max|,|ΔxSS,tmax,Δax,max|), ax,PE,data,max

[0095] The procedure enables a safety assessment for an automated driving vehicle, in particular an autonomous driving vehicle (EGO).

[0096] By changing the longitudinal acceleration a x,EGO,n of the vehicle EGO, the longitudinal accelerations a x,PEThe other vehicles PE1 to PE3, which would be necessary for a collision, are shifted so that they are outside a critical area determined from real-world driving data. The EGO vehicle is thus able to reduce the risk of a collision even before a lane change maneuver into the center lane F2 or to deliberately postpone the start of the lane change maneuver, thereby increasing safety for the EGO vehicle and the other vehicles PE1 to PE3.

[0097] In Fig. 11A is a diagram with a collision probability density pd(a x,PE ) without considering a jerk j and another diagram with a shifted collision probability density range by adjusting a longitudinal acceleration a x,EGO of the vehicle EGO.

[0098] As described above, it is assumed that the initial longitudinal acceleration ax,PEi,init of the other vehicles PE1 to PE3 cannot be measured exactly or only inaccurately and is assumed to be zero for the procedure described here.

[0099] Furthermore, the aim of the procedure is to determine the longitudinal acceleration limits a by adjusting the longitudinal speed of the vehicle EGO x,PE,min , a x,PE,max of the other vehicles PE1 to PE3 into an area of lower probability in order to reduce the collision probability P Kollision to minimize.

[0100] For this purpose, it was defined that the probability of occurrence of the respective longitudinal accelerations a x,PE that lead to a collision, at the same time the collision probability P Kollision describes the collision probability P Kollision corresponds, since the longitudinal acceleration a x,PE is directly related to an overlap of the vehicle surfaces and thus a collision.

[0101] A Fig. 11A and Fig. 11B described problem may arise: If the initial longitudinal acceleration a x,PEi,init However, if one of the other vehicles PE1 to PE3 is already in an area of low occurrence probabilities, it may happen that an optimization of the longitudinal acceleration a x,EGO of the vehicle EGO the longitudinal acceleration limits a x,PE,min , a x,PE,max of the further vehicle PE1 to PE3 into an area which, due to its low probability, is statistically significant in relation to the longitudinal acceleration a x,EGO is optimal, but due to an actual, in particular measured, initial situation Δx MM,init,PEi , Δv x,init,PEi the initial longitudinal acceleration a x,PEi,initof the other vehicle PE1 to PE3 or is approaching it and thus there is a risk of collision, the other vehicle PE1 to PE3 should reduce the initial longitudinal acceleration a x,PEi,init averaged over a lane change.

[0102] According to Fig. 11A calculates the collision probability P Kollision as follows: PCollision=∫ax,PE,minax,PE,maxpdf(ax,PE)dax,PE≈0.5=50% without taking into account the jerk j, whereas the collision probability P Kollision taking into account a Fig. 12A to 12C is j ≈ 0.

[0103] In Fig. 11B shows another diagram in which the probability density pd(a x,PE ) by adjusting the longitudinal acceleration a x,EGO has been postponed.

[0104] The collision probability P Kollision is calculated according to the procedure described above as follows: PCollision=∫ax,PE,minax,PE,maxpdf(ax,PE)dax,PE≈0 and after a new solution approach ≈ 50%.

[0105] The Fig. 12a to 12c show an alternative or additional approach to determining a collision probability P Kollision taking into account the jerk j at a longitudinal acceleration a x,PE of the other vehicles PE1 to PE3. The jerk j represents an instantaneous rate of change of an acceleration a.

[0106] Assuming that the initial longitudinal acceleration a x,PEi,init of the further vehicle PE1 to PE3 can be measured with sufficient accuracy, a difference between the initial longitudinal acceleration a x,PEi,init and the two longitudinal acceleration limits a x,PE,min , a x,PE,max determined, in particular calculated.

[0107] Using these differences, the minimum jerk j x;PE4Δmin and the maximum jerk j x,PE,4Δmaxwhich must be applied averaged over the lane change so that the other vehicle PE1 to PE3 enters the area of the potential collision. This calculation is included in the Fig. 12A and Fig. 12B illustrates.

[0108] The maximum jerk j x,PE,max is calculated as follows: jx,PE,4Δmax=2ax,PE,max−ax,PE,inittFall=2Δax,PE,maxtFall t Fall ∈ t max , t EM depending on the calculation case (21a) to (21c) and (22d) to (22f) for calculating the longitudinal acceleration limits a x,PE,min , a x,PE,max .

[0109] The minimum jerk j x,PE,min is calculated as follows: jx,PE,4Δmin=2ax,PE,min−ax,PE,inittFall=2Δax,PE,mintFall t Fall ∈ t max , t EM depending on the calculation case (21a) to (21c) and (22d) to (22f) for calculating the longitudinal acceleration limits a x,PE,min , a x,PE,max .

[0110] Using a data set, longitudinal jerk ranges are determined from mean values of the longitudinal acceleration change during a lane change using the same method as in the process steps described above, and their probability of occurrence is described using a probability density function, as in Fig. 12C is shown.

[0111] The determined values for the maximum jerk j x,PE,4Δmax and the minimum jerk j x,PE,4Δmin are then used as integral limits for the probability density function of the jerk j when calculating the collision probability P Kollision used.

[0112] In comparison to the process steps described above, this approach also takes into account the jerk j when calculating the collision probability P Kollision taken into account. The longitudinal acceleration a x,EGO of the vehicle EGO can be optimized so that the minimum longitudinal acceleration a x,PE,minand the maximum longitudinal acceleration of the other vehicles PE1 to PE3 require a longitudinal acceleration change effort that has a statistically low probability of occurrence and thus a low collision probability.

[0113] Unlike described above, the probability of occurrence of the jerk j, which is required to reach a mean acceleration that then leads to a collision, is called the collision probability P Kollision used and not the probability of occurrence of the longitudinal acceleration a x,PE .

Claims

[1] Method for the safety assessment of a lane change maneuver in the automated driving mode of a vehicle (EGO) with an environmental sensor system, whereby an environment of the vehicle (EGO) and objects located therein are detected on the basis of signals recorded by the environmental sensor system, whereby - before 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 road section (F), a collision risk is determined by means of hypothetical lane change maneuvers of other vehicles (PE1 to PE3) in the right lane (F3) or the left lane (F1), - based on a maximum lane change duration and a cutting-in moment (t EM ) Longitudinal accelerations (a x,PE) of the other vehicles (PE1 to PE3) are determined, which lead to a collision due to an overlap of the vehicle surfaces of the vehicle (EGO) and the other vehicles (PE1 to PE3), - carrying out the lane change maneuver depending on a relative longitudinal position (Δx MM,init,PEi ) of the vehicle (EGO) to the other vehicles (PE1 to PE3) and initial relative longitudinal velocities (Δv x,init,PEi ) of the vehicle (EGO) to the other vehicles (PE1 to PE3) at the start of a lane change maneuver based on a collision probability (P Kollision ) as a safety measure (S1) and a minimum distance (d x,min ) is assessed as an additional safety measure (S2) if a collision does not occur, - when determining the collision probability (P Kollision ) a height of a jerk (j) a longitudinal acceleration (a x,PE ) of the other vehicles (PE1 to PE3) is taken into account and - the longitudinal acceleration (a x,EGO ) of the vehicle (EGO) is optimized in such a way that a minimum longitudinal acceleration (a x,PE,min ) and a maximum longitudinal acceleration (a x,PE,max ) of the other vehicles (PE1 to PE3) require a longitudinal acceleration change effort, which in each case results in a statistically low collision probability (P Kollision ), characterized by , that the collision probability (P Kollision ) as a safety measure (S1) based on a previously determined probability of expected longitudinal accelerations (a x,PE ) of the other vehicles (PE1 to PE3), based on a Initial situation (Δx MM,init,PEi , Δv x,init,PEi), based on geometric vehicle information of the vehicle (EGO) and geometric vehicle information of the other vehicles (PE1 to PE3), based on starting 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 (a x,EGO,n ) of the vehicle (EGO) is determined. [2] Method according to claim 1, characterized by that the two safety measures (S1, S2) are determined model-based and by changing the longitudinal acceleration (a x,EGO,n ) and / or the initial situation (Δx MM,init,PEi , Δv x,init,PEi ) of the vehicle (EGO) to a next moving vehicle (PE1 to PE3) the collision probability (P Kollision ) and the minimum distance (d x,min ) is influenced during a lane change maneuver. [3] Method according to one of the preceding claims, characterized bythat an evaluation of the minimum distance (d x,min ) as a further safety measure (S2) based on a minimum longitudinal distance between a bumper of the vehicle (EGO) and a bumper of the next vehicle (PE1 to PE3), whereby the minimum distance (d x,min ) is selected during the lane change maneuver after it is determined that the lateral coordinates of the vehicles (EGO, PE1 to PE3) overlap.

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