Motor vehicle with cooperative autonomous driving mode

Abstract

Method for operating a driver assistance device (20) in an automatic driving mode, in which the driver assistance device (20) automatically carries out longitudinal guidance and transverse guidance of a motor vehicle (10), characterized by the steps: - detecting an impending lane change of a third-party vehicle (38) driving in an adjacent lane (36) into the own lane (34) of the motor vehicle (10), - determining a time gap (tpred) likely to occur between the other vehicle (38) and the motor vehicle (10) after the lane change, - if the determined time gap (tpred) is smaller in amount than a predetermined minimum time gap (t), carrying out a longitudinal guidance maneuver on the own lane (34) with the motor vehicle (10), which is designed to increase the expected resulting time gap (tpred) in amount to the minimum time gap (t); wherein, before initiating the longitudinal guidance maneuver, a predetermined lane change criterion for a lane change of the motor vehicle (10) to an alternative lane (40) opposite the adjacent lane (36) is checked and, if the lane change criterion is met, the lane change of the motor vehicle (10) to the alternative lane (40) is carried out instead of the longitudinal guidance maneuver; and wherein the lane change criterion is checked as to whether a distance to a road user traveling in the alternative lane (40) behind the motor vehicle (10) satisfies a predetermined immersion criterion; wherein the method runs cyclically.

Description

[0001] The invention relates to a driver assistance device and a method for operating the driver assistance device in an automatic driving mode, in which the driver assistance device automatically performs longitudinal and lateral guidance of the motor vehicle. A cooperative behavior with a third-party vehicle is realized. The invention also includes a motor vehicle with the driver assistance device.

[0002] When driving, situations arise in which cooperative behavior towards other vehicles is desirable, and this also applies to automated driving. An example is a situation in which another vehicle must or wants to leave its lane because it is ending. This can be the case at a motorway entrance or at a lane merging due to construction work. Another reason for a lane change is the desire to overtake a vehicle in front. If the other vehicle intends to change lanes into the own lane of the host vehicle or ego vehicle, i.e. in this case the motor vehicle controlled by the driver assistance device, accommodating behavior would be desirable in automated driving, with the ego vehicle making way in the own lane so that the other vehicle can carry out the intended lane change safely.

[0003] EP 2 042 398 A2 discloses a method for operating at least one driver assistance system related to the lateral guidance of a motor vehicle. If an impending lane change of a vehicle traveling in an adjacent lane is detected, the driver's own vehicle changes lanes to create a gap for the other vehicle. However, this method can only be implemented if there is also a sufficiently large gap between the vehicles in an adjacent lane for the driver's own vehicle to be able to safely perform the lane change.

[0004] DE 10 2012 011 994 A1 describes a method by which two vehicles can exchange data using standardized C2C communication (C2C - Car-2-Car) and thus coordinate their driving maneuvers. This is intended to avoid critical situations, especially on highways. A disadvantage of this method is that both vehicles must be equipped with the corresponding C2C communication device, which may not be universally available.

[0005] DE 10 2011 106 746 A1 discloses a lane change assistance system in which a longitudinal action space is used to evaluate lane change trajectories, i.e., to answer the question of whether or not the vehicle guided by the driver assistance system can reach a gap in an adjacent lane and merge into it. This system cannot react to an impending lane change by another vehicle.

[0006] DE 10 2012 023 630 A1 describes a method for informing a driver. In this method, a driver's vehicle 10 follows a lead vehicle 30 based on ACC control. An arrow P2 is projected onto the road between vehicles 10 and 30, the length of which corresponds to the distance between the vehicles. ACC control implicitly means that the distance symbolized by arrow P2 corresponds to the minimum distance at which the driver's vehicle 10 should follow the lead vehicle 30. The method does not disclose any time gap that is likely to arise between a driver's vehicle and a leading vehicle after a lane change.

[0007] DE 10 2007 046 688 A1 describes, among other things, that the generation of unnecessary or complete absence of warnings during deliberate driving maneuvers in critical situations can lead to the driver feeling that they cannot rely on the warnings from their driver assistance system and ignoring these warnings or deactivating the driver assistance system. For this purpose, an improved output of warning signals from lateral guidance assistance systems is described, which are adapted to the respective driving situation.

[0008] DE 10 2004 029 369 A1 describes a lane change assistant for motor vehicles. It uses data from the surrounding sensors to detect a window for safely merging into an adjacent lane. In contrast to the present invention, this system focuses on how the driver's own vehicle can safely change lanes, rather than on how to react to a possible lane change by another vehicle into the driver's own lane.

[0009] The invention is based on the object of realizing a cooperative behavior with a driver assistance device towards a foreign vehicle that is planning to change lanes.

[0010] The problem is solved by the subject matter of the independent patent claims. Advantageous developments of the invention result from the features of the dependent patent claims.

[0011] The method according to the invention relates to the operation of a driver assistance device while the device, in an automatic driving mode, automatically guides a motor vehicle through longitudinal and lateral guidance on a dedicated lane, for example, on a highway. This automatic driving mode is known per se and is also referred to as autonomous driving mode. The vehicle referred to below as "motor vehicle" is the so-called "own vehicle" or "ego vehicle," i.e., the vehicle guided by the driver assistance device in automatic driving mode.

[0012] According to the method, an impending lane change by a vehicle traveling in an adjacent lane is detected. The lane change involves the vehicle moving from the adjacent lane into the vehicle's own lane. For the detected lane change, a time gap that is expected to occur between the vehicle and the vehicle after the lane change is predicted, forecasted, or determined. "Time gap" is a technical term used in traffic engineering that represents the speed-related distance information.If the determined time gap is smaller than a predetermined minimum time gap, meaning that the lane change would result in a distance that, given the current speeds of the motor vehicle and the other vehicle, would be smaller than a predetermined safety distance, the driver assistance device performs a longitudinal guidance maneuver with the motor vehicle in its own lane. This longitudinal guidance device is designed to increase the magnitude of the expected time gap to the minimum time gap. The driver assistance device thus ensures the specified safety distance through the longitudinal guidance maneuver.

[0013] In the context of the invention, the longitudinal guidance maneuver refers in particular to the following two maneuvers. If the other vehicle is behind the motor vehicle, i.e., if the other vehicle will pull in behind the motor vehicle due to the lane change, the motor vehicle is accelerated as a longitudinal guidance maneuver. If, however, the other vehicle is in front of the motor vehicle, i.e., if the other vehicle will pull in in front of the motor vehicle due to its lane change, the motor vehicle is decelerated or negatively accelerated as a longitudinal guidance maneuver. Deceleration can therefore include coasting of the motor vehicle, towing of the motor vehicle, braking of the motor vehicle, or a combination thereof.

[0014] The invention also includes a driver assistance device for a motor vehicle, by means of which the method according to the invention can be carried out. The driver assistance device has a control device for carrying out autonomous longitudinal guidance and autonomous lateral guidance of the motor vehicle. In other words, the control device provides the automatic driving mode. The control device can be provided, for example, by a control unit. The driver assistance device also includes an analysis device for detecting an impending lane change of a third-party vehicle traveling in an adjacent lane into the vehicle's own lane and for predicting or determining a time gap likely to arise between the third-party vehicle and the motor vehicle after the lane change.For this purpose, the analysis device can, for example, use map data from a dynamic digital map, as is known per se from the prior art and is designed to accumulate sensor information or sensor signals from environmental sensors of the motor vehicle and to supplement digital information about the lane path of the vehicle's own lane and the adjacent lane with dynamic object information relating to the other vehicle and other road users. The analysis device can, for example, comprise a program module of the aforementioned control unit or a central computing device of the motor vehicle. According to the invention, the driver assistance device is now designed to carry out an embodiment of the method according to the invention.

[0015] The invention provides the advantage that the driver assistance device, in order to provide the cooperative behavior described above with respect to the other vehicle, does not require a free gap in an avoidance lane to avoid the other vehicle and thereby create a gap or space in the own lane so that the other vehicle can perform the intended lane change. Instead, a time gap is created in the own lane that is at least as large as the required minimum time gap.

[0016] Through the following developments of the invention, the impending lane change of the other vehicle is recognized by the fact that at least one of the following lane change criteria is met. In one embodiment, it is recognized based on the digital map that the other vehicle is driving towards the end of the adjacent lane. In particular, it is recognized that the other vehicle has a driving speed that is greater than a predetermined minimum driving speed. In another embodiment, it is recognized that the other vehicle is flashing. One embodiment uses C2C communication by recognizing that the lane change is signaled by a car-to-car communication signal from the other vehicle. One embodiment provides for the detection or recognition that the other vehicle is approaching another vehicle driving ahead in the adjacent lane, i.e. that the other vehicle is traveling faster than the other vehicle driving ahead.In particular, it is checked whether a minimum relative speed is exceeded. One embodiment provides for detecting that the other vehicle is below a predetermined time gap value compared to the other vehicle traveling ahead. The time gap value advantageously takes both the distance and the relative speed into account in combination. Another embodiment provides for detecting that a time-to-collision value of the other vehicle with respect to the other vehicle traveling ahead is less than a predetermined minimum value. The time-to-collision value is the quotient of the distance between the two other vehicles and the approach speed of the other vehicle to the other vehicle traveling ahead.If the minimum value is undercut, cooperative behavior is particularly necessary because an undesirable risky driving maneuver has been detected in the adjacent lane and a spontaneous lane change by the other vehicle is to be expected.

[0017] If the driver assistance device detects that the resulting time gap is smaller than the minimum time gap, the longitudinal guidance maneuver is first planned, for example, using maneuver planning, so that it can be carried out by the control unit of the driver assistance device. In one embodiment, the driver assistance device plans a maneuver as the longitudinal guidance maneuver that provides for longitudinal guidance with a constant acceleration value Aego of the motor vehicle for a predetermined maneuver digestion time T. A constant value can be specified as the maneuver digestion time, which can, for example, be in an interval of 2 seconds to 5 seconds. The maneuver digestion time T can also be adjusted adaptively or dynamically depending on the vehicle's own speed and / or the driving speed of the other vehicle.A constant acceleration value Aego has the advantage that the occupants of the automatically guided vehicle, i.e., the ego vehicle, are subjected to a constant acceleration force during the longitudinal guidance maneuver. As a result, the occupants generally perceive the longitudinal guidance maneuver as less disruptive. Furthermore, a movement of the ego vehicle with constant acceleration is easier to predict for the drivers of the other vehicles.

[0018] In a preferred embodiment, the acceleration value Aego is calculated according to the following formula: Aego=2 / T2*[−t*Vego+Xobj+T*(Vobj−Vego)] if Xobj>0;2 / T2*[t*Vobj+Xobj+T*(Vobj−Vego)] if Xobj<0. where t is the minimum time gap, Vego is the current speed of the motor vehicle, Xobj is the current distance of the motor vehicle to the other vehicle, Vobj is the current driving speed of the other vehicle.

[0019] The formula takes into account whether the other vehicle is driving diagonally in front of the motor vehicle (Xobj > 0) or diagonally behind the motor vehicle (Xobj < 0) in the adjacent lane.

[0020] It should be noted that, depending on the initial situation, the given formula can also produce values ​​with an opposite sign as a result. For example, if the other vehicle is in front of the ego vehicle, this would mean that the distance Xobj is so great that the ego vehicle would have to accelerate in order to reach the safety distance, i.e. the minimum time gap. This can even be useful if, for example, the motor vehicle has not yet reached a desired speed, as set or intended to be achieved by ACC (Automatic Cruise Control). In this case, it makes sense to continue accelerating the motor vehicle until the desired speed or the minimum time gap is reached. If, on the other hand, the other vehicle is very far behind the ego vehicle, a negative acceleration could also be calculated using the given formula.This braking of the vehicle is useless and can therefore be rejected as an invalid result. The vehicle can then ignore the other vehicle.

[0021] The longitudinal guidance maneuver is therefore preferably not performed under every condition. In one embodiment, in a further development of this approach, after the detection of the impending lane change of the other vehicle, a predetermined safety criterion and / or a performance criterion and / or a predetermined comfort criterion is checked, and the longitudinal guidance maneuver is only performed if each checked criterion, i.e., the safety criterion and / or the performance criterion and / or the comfort criterion, is met. Otherwise, i.e., if at least one of the checked criteria is not met, a current driving maneuver of the motor vehicle is continued unchanged. In other words, in this case, the other vehicle is ignored. By providing a check of a safety criterion and / or performance criterion and / or comfort criterion, the method according to the invention can be seamlessly integrated into existing automatic driving modes.

[0022] In a further development of this approach, the comfort criterion includes, at a minimum, that the maximum acceleration value achieved during the entire planned longitudinal guidance maneuver is less than a maximum acceleration value. This results in the advantage of maintaining the maximum acceleration set for the automatic driving mode.

[0023] In a further development, the safety criterion includes at least maintaining a safe distance from a road user in the same lane during the longitudinal guidance maneuver. This advantageously prevents the ego vehicle from being endangered simply to demonstrate cooperative behavior toward the other vehicle.

[0024] In a further development, the performance criterion includes at least that the longitudinal guidance maneuver is technically feasible with the motor vehicle and / or can be performed within a predetermined performance limit. This allows the motor vehicle to be operated gently and / or a shortened maintenance interval to be avoided. For example, thermal overload, e.g., when the drive engine is cold, can be avoided.

[0025] According to the invention, before initiating the longitudinal guidance maneuver, an attempt is first made to swerve into an alternative lane. For this purpose, a predetermined lane change criterion for a lane change of the motor vehicle into the alternative lane is checked. The alternative lane referred to here is not the adjacent lane in which the other vehicle is traveling, but the opposite adjacent lane. Therefore, if the other vehicle is traveling on the right in the adjacent lane next to the vehicle's own lane, the alternative lane is the lane extending to the left of the vehicle's own lane. Conversely, if an other vehicle is in the left adjacent lane, the alternative lane is the right adjacent lane with respect to the vehicle's own lane. If the lane change criterion is met, the vehicle changes lanes into the alternative lane instead of the longitudinal guidance maneuver.This has the advantage of creating more space for the other vehicle. Furthermore, eliminating longitudinal acceleration is beneficial in terms of ride comfort and energy consumption.

[0026] According to the invention, the lane change criterion checks whether the distance to a road user driving in the alternative lane behind the motor vehicle meets a predetermined immersion criterion. For this purpose, it can be assumed, for example, that the road user driving behind the motor vehicle is caused by the lane change of the ego vehicle to decelerate with a constant negative acceleration or deceleration, for example, with a deceleration value in the range of 0.5 m / s. 2 up to 2.5 m / s 2Based on the current distance between the ego vehicle and the road user and the current relative speed of the two, assuming a deceleration, it is possible to determine the minimum time gap that would result between the two if the ego vehicle were to change lanes into the alternate lane. It can be verified whether this would result in a gap that falls below a minimum time gap. In this case, the immersion criterion is not met.Another immersion criterion, however, may allow for a tolerance and assume that the minimum time gap may be undershot, but that, with the other road user's constant deceleration, the undershoot of the minimum time gap only lasts for a predetermined maximum period, which may, for example, be in a range of 2 seconds to 8 seconds, or that the other road user only travels a predetermined maximum distance while undershooting the minimum time gap, which may, for example, be in a range of 0 meters to 500 meters. A similar approach can be taken for a road user traveling in front of the motor vehicle.

[0027] A further description of an immersion criterion can be found, for example, in DE 10 2014 210 174 A1.

[0028] Finally, the invention also includes a motor vehicle, preferably configured as a motor vehicle, in particular as a passenger car or truck. The motor vehicle according to the invention has an embodiment of the driver assistance device according to the invention.

[0029] An exemplary embodiment of the invention is described below. It shows: Fig. 1 a schematic representation of an embodiment of the motor vehicle according to the invention, Fig. 2 a flowchart of an embodiment of the method according to the invention, as it is carried out by the motor vehicle according to Fig. 1 can be carried out, Fig. 3 - Fig. 5 shows a sketch of a driving situation in which the procedure according to Fig. 2 can be carried out.

[0030] The exemplary embodiment explained below is a preferred embodiment of the invention. However, in the exemplary embodiment, the described components of the embodiment each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also considered components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0031] In Fig. 1 shows a motor vehicle 10, which may be a passenger car, for example. The motor vehicle 10 may, for example, have an environmental sensor system 16 on a vehicle front 12 and / or on a vehicle rear 14, as is known per se from the prior art. The environmental sensor system 16 may, for example, be ultrasound-based and / or radar-based and / or lidar-based and / or camera-based. The environmental sensor system 16 can generate sensor signals S that can be dependent on objects (not shown) in an environment or surroundings 18 of the motor vehicle, for example on a position and / or distance of other road users, such as other motor vehicles, i.e., third-party vehicles.

[0032] The motor vehicle 10 can have a driver assistance system or a driver assistance device 20, which can be designed to generate a control signal or check signal C for an actuator device 22 of the motor vehicle 10. The actuator device 22 can be designed to carry out longitudinal and / or transverse guidance of the motor vehicle 10 as a function of the check signal C. The actuator device 22 can be configured in a manner known per se. The driver assistance device 20 can be designed to generate the check signal C as a function of the sensor signals S. As a result, an automatic driving mode is provided by the driver assistance device 20, in which the motor vehicle 10 is automatically guided in traffic while taking other road users into account, without any intervention by a person in the motor vehicle 10.

[0033] For this purpose, the driver assistance device 20 can, for example, have an environment model 24, an analysis device 26, a maneuver planning system 28, and / or a control device 30. The driver assistance device 20 can, for example, be provided as a control unit or as a combination of several control units interconnected via a communications network, or by a central computing unit of the motor vehicle 10. The environment model 24, the analysis device 26, the maneuver planning system 28, and / or the control unit 30 can, for example, be program modules for the aforementioned devices.

[0034] The environment model 24 can, for example, recreate or determine a road course in the environment 18 based on a navigation database 32 and, based on the sensor signals S, enter or map the other road users recognized and detected in the environment 18 as dynamic objects in the recreated road course. In other words, the information from a navigation database 32 and the information from the environment sensor system 16 can be merged in the environment model 24, for example. This creates environment data M. A dynamic digital map from the prior art can be used to provide the environment model 24.

[0035] The analysis device 26 can be designed to, on the basis of environmental data M of the environmental model 24 together with the maneuver planning 28 and the control device 30, Fig. 2. The analysis device 26 uses, for example, the environmental data M to determine whether cooperative behavior is necessary with regard to a foreign vehicle detected in the environment 18 according to the criteria described below. If a reaction, i.e., cooperative behavior, is necessary, a corresponding cooperation signal COOP can be output to the maneuver planning unit 28. On the basis of the environmental data M, the maneuver planning unit 28 can determine trajectory data T of a driving trajectory for a lane change of the motor vehicle 10 or a longitudinal guidance maneuver and transfer the trajectory data T to the control device 30, which, on the basis of the trajectory data T, generates the control signals C for carrying out the driving maneuver described by the trajectory data T.

[0036] The following is based on Fig. 2 the method that can be carried out by the driver assistance device 20 by means of the analysis device 26 and / or the maneuver planning 28 is described in more detail.

[0037] In step S1, it is determined whether a situation exists that could require cooperative behavior. For this purpose, it is checked whether one of the following situations exists. For illustration, Fig. 3, Fig. 4 and Fig. 5. (1) A lane adjacent to the own lane 34, i.e. a neighboring lane 36, ends and there is a third-party vehicle 38 (Obj) on it ( Fig. 3 and Fig. 4). (2) In the adjacent lane 36, a foreign vehicle 38 is rapidly approaching a preceding road user 40, for example a lorry, so that an overtaking intention is anticipated ( Fig. 5).

[0038] Whether an other vehicle 38 (Obj) intends to change lanes can be determined based on the navigation data and the sensor data signals S, i.e., overall, based on the environmental data M. The distance to the nearest end F of an adjacent lane 36 can be determined. A check is then carried out to determine whether this end F is below a specific threshold value in terms of its distance, at which point a reaction should be initiated. If this is the case, the environmental data M is used to determine whether an other vehicle 38 is located there. This vehicle is then referred to as the cooperation object Obj. The side on which the lane end F is located is irrelevant for the method.

[0039] To check a further trigger criterion, the positions and speeds Vobj, Vlkw of all other vehicles in the adjacent lane 36 can be recorded. These are then compared. The system looks for other vehicles whose speed is higher than that of the other vehicle driving immediately in front. A further check is then carried out to determine whether the distance between the two other vehicles is less than a specified minimum time gap t or whether the quotient of distance and approach speed, the so-called time-to-collision value, falls below a certain value. It is then assumed that the other vehicle behind intends to change lanes, i.e., a lane change from the adjacent lane 36 to the own lane 34 is imminent. If the check is negative, in Fig. 2 is marked with a minus sign "-", monitoring is started from the beginning. This means that the procedure runs cyclically as long as one of the scenarios described above is present. If the cooperation object Obj, i.e., the foreign vehicle 38, behaves cooperatively itself, contrary to expectations, this will be detected in the next run. Accordingly, only a reduced reaction would then be necessary.

[0040] Once the cooperation object Obj has been detected, a second step can be used to distinguish where the potential cooperation object Obj, in this example the other vehicle 38, is located relative to the ego vehicle Ego, i.e. the motor vehicle 10. Depending on whether it is in front of the vehicle, i.e., an object distance Xobj between the motor vehicle 10 and the other vehicle 38 is greater than 0, or behind the vehicle, i.e., the object distance Xobj is less than 0, braking or acceleration should occur later.

[0041] In a third step S10, the necessity of a reaction can be checked based on the distance Xobj and the relative speed, i.e. the speed difference between the own speed Vego of the motor vehicle 10 and the driving speed Vobj of the other vehicle 38.

[0042] If the other vehicle 38 is in front of the motor vehicle 10, no reaction is necessary if: - the other vehicle 38 is significantly faster than the motor vehicle 10, and - the distance Xobj to the other vehicle 38 is already greater than a predetermined time gap t.

[0043] If the other vehicle 38 is behind the motor vehicle 10, no reaction is necessary if: - the other vehicle 38 is significantly slower than the motor vehicle 10, i.e. the speed difference is greater than a predetermined minimum value, and - the distance Xobj to the other vehicle 38 is already greater than a predetermined time gap t.

[0044] In this case, it is possible to return to step S1. To check whether the minimum time gap t has been maintained, a predicted time gap tpred can be determined, which results from the assumption that the other vehicle 38 changes from the adjacent lane 38 to the own lane 34 at a distance Xobj and that the motor vehicle 10 maintains its own speed Vego. If |tpred| < t then results, the minimum time gap has been exceeded. In this case, a check is carried out to determine whether an evasive maneuver or a longitudinal guidance maneuver can be performed. Steps S1 to S3 can be carried out, for example, by the analysis device 26. If the condition |tpred| < t is met, the cooperation signal COOP can be generated.

[0045] In a step S4, the feasibility of a lane change of motor vehicle 10 into an alternative lane 40 can be checked for the two cases described above. For this purpose, it is determined whether a target lane, i.e., an alternative lane 40, even exists and whether it is permitted to be entered, and whether there is a sufficiently large gap in the traffic there for motor vehicle 10 to merge into. This safety check can be performed, for example, based on the described entry criterion. If both criteria are met, the lane change Chng is performed, and the process is completed, meaning that the process can return to step S1.

[0046] If a lane change is not possible, the only possible reaction is in the own lane, i.e., in the own lane 34. In a fifth step S5, a different reaction is therefore carried out depending on the relative position Xobj of the other vehicle 38: (1) If the other vehicle 38 is in front of the ego vehicle, i.e. the motor vehicle 10, a constant deceleration Aego is calculated in order to follow this object, i.e. the motor vehicle 10, at a distance of a predetermined time gap t when the object speed Vobj is reached. (2) If, however, the other vehicle 38 is located behind the motor vehicle 10, a constant acceleration Aego should be calculated in order to drive ahead of this object at a distance of a predetermined time gap t when the object speed Vobj is reached.

[0047] The other vehicle 38 is assumed to be unaccelerated.

[0048] The constant acceleration Aego for the motor vehicle 10 is calculated in particular as follows: Aego=2 / T2*[−t*Vego+Xobj+T*(Vobj−Vego)] if Xobj>0;2 / T2*[t*Vobj+Xobj+T*(Vobj−Vego)] if Xobj<0.

[0049] This means: If the object is in front of motor vehicle 10, it decelerates at a constant rate of negative acceleration Aego; if it is behind it, it accelerates at a constant rate of acceleration Ago. This creates the space for the other vehicle 38 to change lanes.

[0050] Finally, in a sixth step S6, a check is made to determine whether the calculated acceleration value Aego does not fall below a maximum deceleration Abrk specified for technical reasons or by comfort or safety requirements, meaning that excessive braking is required, or whether it does not exceed a corresponding maximum acceleration Aacc. A safety criterion can also be specified to verify that no other road users are endangered. A negative acceleration less than Abrk could impede other road users due to the longitudinal guidance maneuver. A positive acceleration greater than Aacc could endanger other road users.If the calculated acceleration value Aego is technically feasible and within the comfort specifications, and if no danger to other road users is discernible, the braking or acceleration maneuver, i.e., the longitudinal guidance maneuver, is communicated in a step S7 in the form of the trajectory data T to the control device 30 for execution, which then carries out the longitudinal guidance maneuver. This completes one run of the method, and step S1 can be started again. If not all specifications are met, cooperative behavior with the other vehicle 38 is not possible under the given circumstances. In this case, no acceleration (braking or accelerating) of the own motor vehicle 10 occurs.

[0051] As already explained, the acceleration value Aego can also have an opposite sign depending on the initial situation. Therefore, in step S6, the following check is preferentially performed: (1) The third-party vehicle 38 is in front of the own motor vehicle 10: - whether the calculated deceleration does not exceed a specified maximum value and - whether the calculated delay is actually a delay, i.e. the value is negative, and - whether this would not impede any other vehicle in the own lane 34, i.e. a time gap t to another road user in the own lane 34, assumed to be accelerating at a constant rate. A tolerance value can also be provided here which allows the minimum time gap t to be undershot for a predetermined period of time, for example 3 seconds.

[0052] If all three criteria are met, constant braking is carried out with the calculated deceleration Aego and the process is then terminated after this step S7. (2) If the third-party vehicle 38 is behind the own vehicle 10, the following shall be checked: - whether the calculated acceleration Aego does not exceed a predetermined maximum value Aacc and - whether it is greater than 0, i.e. whether it should not be braked, and - whether another road user on the own lane 34 would be obstructed, i.e. here again the minimum time gap t would not be undercut or at least would only be undercut for the specified maximum time period.If all three criteria are met, constant acceleration is carried out with the calculated acceleration Ago and the method is terminated with this step S7.

[0053] As already explained, the Fig. The process shown in Figure 2 occurs cyclically as long as one of the scenarios described above exists.

[0054] The formula is based on the assumption that after the maneuver digester T the distance Xobj should satisfy the condition: |Xobj|=t*Vego if Xobj>0, t*Vobj if Xobj>0.

[0055] The formula has a limiting case, which is almost impossible in reality, where both vehicles are traveling at exactly the same height, i.e. Xobj = 0. Should this limiting case occur by chance, the object Obj, i.e. the foreign vehicle 38, is not accepted as a cooperation partner, and the procedure according to Fig. 2 is therefore not carried out. However, since this condition can only occur for a very short time, the detection and reaction to it will then be carried out in the next cycle of the procedure according to Fig. 2, namely with respect to one of the two described cases Xobj > 0 or Xobj < 0.

[0056] In the case of motor vehicle 10, the described successive testing of cooperative behavior options results in the following essential process: 1. Does the situation require cooperative behavior of your own vehicle 10? 2. Is it possible to change lanes to an alternative lane, number 40? If so, do so. 3. If no, determine the required acceleration / deceleration Aego. If these specified limits do not exceed Abrk and Aacc, perform acceleration / deceleration Aego; otherwise, do not perform acceleration / deceleration.

[0057] To understand the functioning of the motor vehicle 10 according to the invention, reference is made to the following three examples and Fig. 3 to Fig. 5. In Fig. 3 to Fig. 5 are elements that are functionally equivalent elements from Fig. 1 and Fig. 2, with the same reference numerals as in Fig. 1 and Fig. 2.

[0058] In a first scenario, which is Fig. As shown in Figure 3, an object vehicle 38 is located on an ending highway lane 36, which may end, for example, due to a construction site, to the left of an ego vehicle 10. The object vehicle 38 travels at a constant speed Vobj and is located in front of the ego vehicle 10. Furthermore, the distance Xobj is smaller than the product of the minimum time gap t multiplied by the speed Vego of the ego vehicle 10. The two vehicles 10, 38 can have the same speed Vobj = Vego. To the right of the ego vehicle 10, there is no further lane, so there is no alternative lane.

[0059] Following the described procedure, it is now recognized that one of the specific situations applies (step S1). Since a criterion for "no reaction necessary" (steps S2 and S3) is not met and a lane change is not possible (step S4), a deceleration Aego is now calculated (step S5). If the object vehicle 38 is still far enough away that this deceleration is not too great, i.e., less than Abrk (step S6), the ego vehicle 10 will now brake accordingly and allow the object vehicle 38 to merge.

[0060] In a second scenario, which is Fig. As shown in Figure 4, the object vehicle 38 is located on a motorway entrance 36 to the right of the ego vehicle 10. The object vehicle 38 has a higher speed Vobj than the ego vehicle 10 (Vobj > Vego) and is located behind the ego vehicle (Xobj < 0). To the left of the ego vehicle 10, there is another lane 40. However, traffic is heavy there, meaning there is no avoiding gap into which the ego vehicle 10 could swerve. Directly in front of the ego vehicle 10, another road user is traveling in the own lane 34. The road user could, for example, be a truck traveling slower than the ego vehicle 10.

[0061] According to the method, the driver assistance device 20 now recognizes that one of the specific situations applies (step S1). A criterion for "no reaction necessary" (steps S2 and S3) does not apply. Furthermore, due to the heavy traffic, the ego vehicle 10 cannot change lanes (step S4). A required acceleration Aego is now calculated (step S5). However, an acceleration maneuver would result in the vehicle driving too close to the truck. Therefore, the method is aborted (step S6) because no reaction is possible. The object vehicle 38 on the merging lane 36 must wait.

[0062] In a third scenario, which is Fig.As illustrated in Figure 5, an object vehicle 38 is located in the right lane 36 of a highway. A slow-moving truck 42 is traveling in front of the object vehicle 38 at a speed Vlkw. The distance XIkw between the object vehicle 38 and the truck 42 is already smaller than the product of the minimum time gap t multiplied by the speed Vobj of the object vehicle 38. The ego vehicle 10 is approaching from behind in the middle lane 34 at a high speed Vego > Vobj. The left lane 40 of the highway is clear.

[0063] First, it is detected that the object vehicle 38 intends to overtake the truck 42 (intention to change lanes, step S1). This can be detected by the relatively short distance XIkw and the higher speed Vobj > Vlkw. Since the ego vehicle 10 is significantly faster (Vego > Vobj), a reaction is required (steps S2 and S3). Because another, free lane 40 is available on the left, the ego vehicle 10 moves to the left into this lane (step S4). This completes the cycle for the process. The object vehicle 38 can then comfortably overtake the truck 42, and the ego vehicle 10 does not need to brake.

[0064] The described method results in a simple, predictable, and reproducible behavior of the driver assistance device 20. The method does not require direct communication with the object vehicle 38. Furthermore, the robustness of the method is ensured by the assumption of selfish cooperation objects, since the cooperation objects, i.e., the other vehicle 38, can have an acceleration Aobj equal to 0, thus, it does not have to change its driving behavior with respect to speed.

[0065] Since primarily only logical queries are performed, which, if answered negatively, lead to the termination of the procedure, and since there are still only a few calculations overall, the overall computational effort required to carry out the procedure is low. This also allows for the use of particularly inexpensive and simple hardware to implement the procedure, i.e., the driver assistance device 20. Furthermore, the various maneuvers provided make it suitable for many different situations: vehicle in front of / behind the own vehicle 10, lane end left / right in relation to the own lane 34, an indicated overtaking request of the other vehicle 38.

[0066] Overall, the example shows how the invention can be used to successively test options for cooperative behavior towards other road users.

Claims

[1] Method for operating a driver assistance device (20) in an automatic driving mode, in which the driver assistance device (20) automatically carries out a longitudinal guidance and a transverse guidance of a motor vehicle (10), characterized by the steps: - detecting an impending lane change of a third-party vehicle (38) driving in an adjacent lane (36) into the own lane (34) of the motor vehicle (10), - determining a time gap (tpred) likely to occur between the other vehicle (38) and the motor vehicle (10) after the lane change, - if the determined time gap (tpred) is smaller in amount than a predetermined minimum time gap (t), carrying out a longitudinal guidance maneuver on the own lane (34) with the motor vehicle (10), which is designed to increase the expected resulting time gap (tpred) in amount to the minimum time gap (t); wherein, before initiating the longitudinal guidance maneuver, a predetermined lane change criterion for a lane change of the motor vehicle (10) to an alternative lane (40) opposite the adjacent lane (36) is checked and, if the lane change criterion is met, the lane change of the motor vehicle (10) to the alternative lane (40) is carried out instead of the longitudinal guidance maneuver; and wherein the lane change criterion is checked as to whether a distance to a road user traveling in the alternative lane (40) behind the motor vehicle (10) satisfies a predetermined immersion criterion; wherein the method runs cyclically. [2] Method according to claim 1, wherein the impending lane change is detected by at least one of the following lane change criteria being met: - the other vehicle (38) is driving towards a lane end (F) of the adjacent lane (36), - the other vehicle (38) flashes and / or signals the lane change by means of a car-to-car communication signal, - the other vehicle (38) collides with another other vehicle (42) driving in front in the adjacent lane (36), - the other vehicle (38) falls below a minimum time gap (t) to the other other vehicle (42), - a time-to-collision value of the other vehicle (38) with respect to the other other vehicle (42) is less than a predetermined minimum value. [3] Method according to one of the preceding claims, wherein, as the longitudinal guidance maneuver, the motor vehicle (10) is accelerated if the other vehicle (38) is located behind the motor vehicle (10), and the motor vehicle (10) is decelerated if the other vehicle (38) is located in front of the motor vehicle (10). [4] Method according to one of the preceding claims, wherein the driver assistance device (20) plans as a longitudinal guidance maneuver such a maneuver which has a longitudinal guidance with an acceleration value Aego of the motor vehicle (10) for a predetermined maneuver digestion T, wherein the acceleration value Aego is kept constant or within a predetermined tolerance interval during the maneuver digestion T. [5] Method according to claim 4, wherein the acceleration value Aego is calculated as: Aego= 2 / T2*[−t*Vego+Xobj+T*(Vobj−Vego)] if Xobj>0; 2 / T2*[t*Vobj+Xobj+T*(Vobj−Vego)], if Xobj>0, where t is the minimum time gap, Vego is a current speed of the motor vehicle (10), Xobj is a current distance of the motor vehicle (10) to the other vehicle (38), Vobj is a current driving speed of the other vehicle (38). [6] Method according to one of the preceding claims, wherein after detection of the impending lane change, a predetermined safety criterion and / or a performance criterion and / or a predetermined comfort criterion is checked and the longitudinal guidance maneuver is only carried out if each checked criterion is met, and otherwise a current driving maneuver is continued unchanged. [7] Method according to claim 6, wherein the comfort criterion at least comprises that during the entire planned longitudinal guidance maneuver, a maximum achieved acceleration value is smaller in magnitude than a maximum acceleration value (Acc, Abrk). [8] Method according to claim 6 or 7, wherein the safety criterion at least comprises that a safety distance from a road user (lorry) located in the own lane (34) is maintained by the longitudinal guidance maneuver. [9] Method according to one of claims 6 to 8, wherein the performance criterion at least comprises that the longitudinal guidance maneuver is technically feasible with the motor vehicle and / or feasible within a predetermined performance limit. [10] Driver assistance device (20) for a motor vehicle (10), with - a control device (30) for carrying out an autonomous longitudinal guidance and an autonomous lateral guidance of the motor vehicle (10) and - an analysis device (26) for detecting an impending lane change of a foreign vehicle (38) traveling in an adjacent lane (36) into the own lane (34) of the motor vehicle (10) and for determining a time gap (tpred) likely to arise between the foreign vehicle (38) and the motor vehicle (10) after the lane change, characterized by that the driver assistance device (20) is designed to carry out a method according to one of the preceding claims. [11] Motor vehicle (10) with a driver assistance device (20) according to claim 10.

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