Method for operating a driver assistance system of a motor vehicle, related at least to the

Abstract

The invention relates to a method for operating a driver assistance system (3) relating to at least longitudinal guidance of a motor vehicle (1), comprising: providing (S2) sensor information (22) describing at least one other motor vehicle (20) located in front of the motor vehicle (1) in a direction of travel (18) of the motor vehicle (1); determining (S3) hazard warning light information (24), which describes whether the at least one other motor vehicle (20) has an activated hazard warning light, by applying a hazard warning light identification criterion (23) to the provided sensor information (22); if at least one other motor vehicle (20) has a hazard warning light activated on the basis of the determined hazard warning light information (24), increasing (S5) the time difference (25) by a predetermined time interval (26); the time difference value (25) describes a maximum time difference between a triggering time of a function of the driver assistance system (3) and a collision point of a predicted collision between the motor vehicle (1) and an obstacle around the motor vehicle (1); and operating (S6) the driver assistance system (3) taking into account the increased time difference value (25).

Description

Field of the Invention

[0001] The present invention relates to a method for operating a driver assistance system for a motor vehicle. The present invention also relates to a motor vehicle, a control device for a motor vehicle, and a computer program product for performing such a method. Background Art

[0002] A motor vehicle can have a driver assistance system that relates to the longitudinal guidance of the motor vehicle. The driver assistance system can be designed to actuate, for example, at least semi-automatically, in particular fully automatically, the longitudinal guidance of the motor vehicle. Thus, the driver assistance system can actuate, for example, the braking system of the motor vehicle. Such a driver assistance system is, for example, an autonomous emergency braking system (AEB). Alternatively or additionally, the driver assistance system can be designed to output a warning about obstacles in the surroundings of the motor vehicle and thus, for example, recommend manual actuation of the longitudinal guidance by the driver of the motor vehicle.

[0003] A predetermined time difference is generally taken into account for actuating the driver assistance system related to the longitudinal guidance of the motor vehicle. This describes the time difference that can be between the triggering time of the driver assistance system and the collision time at which a predicted collision of the motor vehicle with an obstacle occurs. The time difference can also alternatively be referred to as the time to collision (TTC). When an obstacle with which the motor vehicle may collide is detected, it is continuously checked whether the time difference has been reached. Once reached, for example, the functions of the driver assistance system are triggered, such as autonomous emergency braking of the motor vehicle and / or outputting a warning message. The time difference is generally provided as a permanent predetermined value, which can be stored in the driver assistance system.

[0004] However, it may occur that, for example, at the moment when an obstacle is detected, the speed at which the motor vehicle approaches the obstacle is too great such that, taking into account the predetermined time difference, a collision with the obstacle cannot be prevented by means of the driver assistance system. Thus, the driver assistance system cannot be operated reasonably in every case.

[0005] US 2018 / 0257646 A1 discloses a vehicle control device including a rear-end collision impact safety system that can perform safety control in the presence of a rear-end collision risk. Summary of the Invention

[0006] It is an object of the present invention to provide a solution by which a driver assistance system for a motor vehicle can be operated particularly reasonably.

[0007] This object is achieved by the subject matter of the independent claims.

[0008] A first aspect of the present invention relates to a method for operating a driver assistance system of a motor vehicle, the driver assistance system being at least related to the longitudinal guidance of the motor vehicle. The driver assistance system is preferably designed to actuate the longitudinal guidance of the motor vehicle at least semi-automatically, in particular fully automatically.

[0009] The present invention is at least based on the finding that the driver assistance system cannot operate reasonably in each case with a permanently predetermined time difference (time to collision, TTC). Therefore, at least in some cases, the time difference is variable. An increase in the time difference depending on the situation is particularly reasonable in order to prevent a collision with an obstacle even more reliably compared to the operation of a driver assistance system using a permanently predetermined time difference.

[0010] The method includes providing sensor information that describes at least one other motor vehicle located in front of the motor vehicle in the travel direction of the motor vehicle. The other motor vehicle is, for example, another motor vehicle traveling in front of the motor vehicle. The other motor vehicle can be located in the lane in which the motor vehicle itself is traveling and / or in a lane adjacent to the lane in which the motor vehicle is traveling. The other motor vehicle can currently be traveling or can be stationary. The sensor information describes, for example, all other motor vehicles located in the capture area of the sensor device that captures and provides the sensor information. The capture area is, for example, at least a part of the surroundings of the motor vehicle in the area in front of the motor vehicle. It can be provided that the travel direction of the other motor vehicle corresponds to the travel direction of the motor vehicle, so that, for example, oncoming other motor vehicles, which are, for example, located in a different lane from the motor vehicle, are not taken into account. In this way, the method can be restricted to considering sensor information that only describes other motor vehicles traveling in front of and / or stationary in front of the motor vehicle and, for example, excludes oncoming traffic vehicles. However, generally any other motor vehicle described by the sensor information can be considered.

[0011] The sensor information is preferably transmitted to and thus provided to the control device of the motor vehicle. The control device can then provide the sensor information. The control device is a computing unit and is designed to evaluate the sensor information for further method steps of the method. The method steps described below are preferably all executed by the control device of the motor vehicle. In addition, the control device is designed to operate the driver assistance system, that is, to execute at least one function of the driver assistance system. Therefore, the control device is designed to generate at least one control command for, for example, the braking system of the motor vehicle and provide it to the braking system.

[0012] The method includes determining hazard warning light information by applying a hazard warning light detection criterion to the provided sensor information. The hazard warning light information describes whether at least one other motor vehicle has an activated hazard warning light. Thus, it is intended to check whether the corresponding other vehicle described by the sensor information currently has an activated hazard warning light system. The hazard warning light is implemented, for example, by a lighting unit of the other motor vehicle. When the warning light is activated, usually all turn signals of the other motor vehicle are simultaneously turned on and flash. For example, whenever it is necessary to inform following road users, such as a sudden deceleration of a motor vehicle, the end of a traffic jam, the last vehicle in a column, an accident, the towing of another vehicle, and / or an upcoming driving maneuver of a bus, especially a school bus or a coach, the other motor vehicle travels with an activated hazard warning light. There may be alternative or additional situations in which the other motor vehicle activates the hazard warning light. Thus, an other motor vehicle traveling and / or standing still with an activated hazard warning light clearly indicates that there may be an obstacle to this motor vehicle. For this purpose, it is determined according to the present invention whether at least one other motor vehicle around the motor vehicle has activated its hazard warning light. The hazard warning light detection criterion is, for example, an algorithm and / or a rule based on which the sensor information is evaluated to determine which other motor vehicle described by the sensor information currently has an activated hazard warning light and which does not.

[0013] If, according to the determined hazard warning light information, at least one other motor vehicle has an activated hazard warning light, the time difference is increased by a predetermined time interval. The time difference describes the time difference, at most located, especially allowed to be located, between the triggering time of the function of the driver assistance system and the predicted collision time between the motor vehicle and an obstacle around the motor vehicle. The time difference is usually referred to as the time to collision (TTC) or the time to collision value in the case of a driver assistance system. The time difference can be, for example, 1.4 seconds. In this case, the function of the driver assistance system is triggered at the latest 1.4 seconds before the calculated predicted time of collision of the motor vehicle with the obstacle, that is, 1.4 seconds before the collision time. For example, the function of the driver assistance system includes at least semi-automatically, especially fully automatically, braking the motor vehicle and / or outputting a warning message in the motor vehicle. The obstacle can be an other motor vehicle with an activated hazard warning light and / or another object around the motor vehicle. Thus, instead of predicting a collision of the motor vehicle with the obstacle, it can be assumed that there is a predicted collision of the motor vehicle with at least one other motor vehicle with an activated hazard warning light.

[0014] The predetermined time interval is a fixed time value. The time interval is, for example, 0.5 seconds. In the above example, the time difference thus increases from the initial 1.4 seconds by 0.5 seconds to a total of 1.9 seconds.

[0015] Taking into account the increased time difference, the driver assistance system then operates. Thus, for example, 1.9 seconds is assumed by the driver assistance system as the predetermined time difference instead of the original 1.4 seconds. Accordingly, the reaction time during which the function of the driver assistance system is activated is extended because the at least semi-automatic deceleration of the motor vehicle or another function of the driver assistance system starts earlier than the original time difference. The function intensity of the driver assistance system can remain unchanged.

[0016] By this method, by taking into account the hazard warning light information, potential dangerous situations can be detected particularly quickly, so that, for example, the braking or other functions of the driver assistance system can be activated particularly early. This early activation is achieved by increasing the time difference. In this way, a particularly reliable operation of the driver assistance system is possible.

[0017] One advantageous exemplary embodiment provides that the predetermined time interval is determined taking into account at least the intrinsic speed of the motor vehicle. The time interval by which the time difference is increased is thus not constant but depends at least on the speed at which the motor vehicle is currently traveling. The intrinsic speed can be determined by sensors of the motor vehicle designed for this purpose. The sensors capture, for example, odometer data. For example, the faster the motor vehicle is traveling, i.e., the higher the intrinsic speed, the larger the predetermined time interval that can be selected. Instead of the above-mentioned 0.5 seconds, the time interval can be increased, for example, to 0.7 seconds, 1 second or even longer than 1 second. If the motor vehicle is traveling slowly, for example 30 km / h or even lower, the time interval can be reduced to, for example, only 0.3 seconds. Time intervals other than those mentioned here as examples are also possible. In this way, a reasonable time difference is always selected based on the current speed of the motor vehicle, depending on the situation.

[0018] Another exemplary embodiment provides that the predetermined time interval is determined taking into account at least the relative speed of the motor vehicle with respect to at least one other motor vehicle. Thus, for example, not only the intrinsic speed of the motor vehicle can influence the time interval, but also the speed difference between the motor vehicle and the other motor vehicle can influence the time interval. Thus, the traveling speed of this motor vehicle is considered in comparison with other motor vehicles having activated hazard warning lights. The relative speed thus defines the intrinsic speed with respect to the speed of the other motor vehicle. For example, if the other motor vehicle is already at a standstill, the relative speed is greater than the case where the other motor vehicle is still traveling, so the speed is greater than 0 km / h. The higher the relative speed, the larger the predetermined time interval generally is. To determine the relative speed, for example, sensor information and / or the determined or measured intrinsic speed of the motor vehicle can be evaluated. A particularly reasonable predetermined time interval is determined by taking into account the relative speed of the motor vehicle.

[0019] When increasing the time reference value, the determined time interval is always taken into account. For this purpose, it can be stored at least temporarily in the storage unit of the control device.

[0020] In a preferred exemplary embodiment, it is provided that if a plurality of other motor vehicles have activated hazard warning lights, distance information is determined for each of the plurality of other motor vehicles. The distance information describes the distance between the motor vehicle and the respective other motor vehicle. For example, sensor information can be considered to determine the distance information. For this purpose, for example, the sensor information can be evaluated, which describes the distance to the respective objects around the motor vehicle. The sensor information evaluated here can be captured and provided, for example, by a radar device, a lidar device, and / or an ultrasonic sensor. Alternatively or additionally, the distance information can be determined from a camera image and thus from the static and / or moving image data of the camera unit. Known methods can be used to determine the distance between the motor vehicle and the objects around the motor vehicle, where the objects are, for example, other motor vehicles here.

[0021] Then the relative speed of the motor vehicle with respect to the other motor vehicle for which the minimum distance information has been determined is considered. Thus, it is checked for which one of the plurality of other motor vehicles the minimum distance information has been determined. Then, this other motor vehicle is selected as the single other motor vehicle and considered within the scope of the method. For example, the remaining other motor vehicles can be ignored. When determining the time interval, only the relative speed with respect to the selected other motor vehicle is considered. Since the motor vehicle with the minimum distance information is the other motor vehicle arranged closest to the motor vehicle, the expected potential obstacles for the motor vehicle are thus considered in this way, because the other motor vehicle with activated hazard warning lights arranged closest to the motor vehicle is particularly likely to represent an obstacle for the motor vehicle. In this way, the risk of collision with an obstacle, namely the risk of collision with the selected other motor vehicle, can be prevented particularly reliably.

[0022] In this exemplary embodiment, the other motor vehicle with the minimum distance information can be a motor vehicle traveling in an adjacent lane and thus not in the same lane as the motor vehicle. The selected other motor vehicle can be an obstacle arranged on the side of the motor vehicle, especially not on its predicted travel trajectory. It is presumed that in the case of a motor vehicle in motion or at a standstill having activated hazard warning lights, passengers will especially suddenly leave the vehicle and become an obstacle for the motor vehicle. Since other motor vehicles with activated hazard warning lights located in adjacent lanes are considered here, as a precautionary measure for this situation, the time difference is increased. This is first reasonable in the inner-city area, where the likelihood that the passengers of other motor vehicles will leave it is relatively high.

[0023] Another exemplary embodiment provides that if a plurality of other motor vehicles have activated hazard warning lights, it is determined which of these other motor vehicles are located in the same lane as the motor vehicle. In this case, the lane is the lane of the road on which the motor vehicle and the plurality of other motor vehicles are traveling. Distance information is determined only for the other motor vehicles determined in this case. Thus, distance information is determined only for the other motor vehicles or for at least one other motor vehicle located in the same lane as the motor vehicle. The distance information describes the distance between the motor vehicle and the determined other motor vehicle as described above. The relative speed of the motor vehicle with respect to the other motor vehicle for which the minimum distance information is determined is considered. Thus, if distance information is determined for a plurality of other motor vehicles in the same lane, the minimum distance information is also selected and the associated other motor vehicle is considered as the only motor vehicle. Thus, in this case, the motor vehicle is generally identified as traveling in the motor vehicle lane directly in front of the motor vehicle. Thus, motor vehicles in adjacent lanes are not considered, especially in the case of a multi-lane highway, and only other motor vehicles that the motor vehicle is directly approaching are considered because it is in the same lane. In this way, the method is deliberately designed to be applicable to a possible imminent frontal collision of the motor vehicle with other motor vehicles traveling ahead and thus to typical collision situations in road traffic.

[0024] A particularly preferred exemplary embodiment provides that a predetermined time interval is determined taking into account at least the determined minimum distance information. Thus, for example, in addition to or alternatively to the intrinsic speed and / or the relative speed, it can also be considered how far the nearest other motor vehicle among the plurality of motor vehicles is from the motor vehicle. Depending on how far the other motor vehicle is from the motor vehicle, the time interval can thus be predetermined to be larger or smaller. This results in the time interval being adapted to the situation in a particularly different way.

[0025] According to another exemplary embodiment, it is provided to check whether the intrinsic speed of the motor vehicle is greater than a predetermined speed difference. The speed difference is a value predetermined for the driver assistance system. It describes the speed difference by which the intrinsic speed can be reduced at most by the driver assistance system. It is assumed here that the driver assistance system cannot semi-automatically decelerate the motor vehicle from any arbitrary intrinsic speed to a standstill, but limits the at least semi-automatic speed reduction that can be achieved with the driver assistance system to a maximum speed difference. This is described by the speed difference. For example, this can be 60 km / h.

[0026] If the inherent speed is greater than a predetermined speed difference, the time difference increases by a predetermined other time interval, which is greater than the predetermined time interval. Thus, in a motor vehicle traveling at, for example, 120 km / h, the speed difference is permanently predetermined, which is lower than the inherent speed of the motor vehicle, for example 60 km / h. In this example, the current inherent speed of 120 km / h is semi-automatically, in particular fully automatically, reduced to an inherent speed of at most 60 km / h by means of a driver assistance system. Thereafter, for example, it is necessary to manually perform holding the brake until stationary or at a speed below 60 km / h, for example by the driver of the motor vehicle actuating the brake pedal of the motor vehicle. Considering that the driver may have a delayed reaction because he relies on the driver assistance system, the time difference increases by an even greater time interval than the time interval provided previously. For example, the time interval is defined as 1 second, 1.5 seconds, 2 seconds or even longer, rather than 0.5 seconds mentioned as an example. Here it is stipulated that the time difference increases by a predetermined other time interval, rather than the predetermined time interval. If there are limitations to the braking function of the driver assistance system, a reasonable additional increase in the time difference can thus be achieved.

[0027] In another exemplary embodiment, it is stipulated that the predetermined other time interval is determined by taking into account at least the reaction time of the driver of the motor vehicle. For example, the reaction time specific to or dependent on the driver can be known and taken into account. This can be stored, for example, in the user profile of the driver, which can be stored in and / or loaded into the motor vehicle if provided by an external computing unit. Alternatively or additionally, the reaction time is usually predetermined. The reaction time that is usually predetermined can be, for example, between 1 second and 3 seconds. Then, the time interval is, for example, at least the reaction time, in particular the time interval determined taking into account the inherent speed, relative speed and / or minimum distance information plus the reaction time. In this way, additional protection is achieved by taking into account the reaction time of the driver.

[0028] In another exemplary embodiment, it is provided to continuously determine and check the hazard warning light information. The check should be understood to mean checking whether at least one other motor vehicle with an activated hazard warning light has been detected based on the hazard warning light information, or for example whether no other motor vehicle with an activated hazard warning light has been detected. Once it is determined based on the determined hazard warning light information that no other motor vehicle has an activated hazard warning light, the time difference is again decreased by a predetermined time interval, and the driver assistance system is again operated taking into account the decreased time difference. In other words, as long as at least one other motor vehicle with an activated hazard warning light is detected by evaluating the sensor information, the increase in the time difference is maintained. Once the other motor vehicles located in the capture area of the sensor device of the motor vehicle providing the sensor information still do not have an activated hazard warning light, the previously increased time difference is again decreased to its starting value. Thus, the time difference is again reset to the original time difference. In this way, it is obvious that the method according to the invention is only intended for special cases and is not intended to change the predetermined time difference without limit in chronological order.

[0029] According to another exemplary embodiment, it is provided that the functions of the driver assistance system include a warning of a predicted collision, a brake preparation of at least one brake of the motor vehicle braking system and / or a braking by at least one brake of the braking system. Thus, the driver assistance system can be designed only for collision warning and can therefore, for example, indicate to the driver of the motor vehicle the time when braking should be performed. Taking into account the increased time difference, a warning message output is provided in this case. For example, an output unit for warnings can be provided in the motor vehicle. The output unit can be designed for acoustic and / or optical output. Thus, the output unit is, on the one hand, for example, a display unit, such as a display screen, in particular a touch-sensitive display screen, and / or a head-up display, and / or, on the other hand, a speaker unit having at least one speaker. The output unit can be a component of the motor vehicle and / or can be included by a mobile terminal located in the motor vehicle, in particular a smartphone or a tablet. The control device transmits, for example, measures for warning (such as a warning message) to the output unit.

[0030] The brake preparation as a function can be, for example, preparing at least one brake of the braking system for an upcoming braking operation. For this purpose, the brake can be brought into an initial state of braking, for example, by at least one mechanical, pneumatic and / or hydraulic measure. This has the effect that subsequent braking can be performed particularly quickly by the brake if required. Preferably, it is provided that the driver assistance system can actually actuate at least one brake of the braking system and thus actually perform braking, in particular braking to a stop. Thus, the driver assistance system is a driver assistance system related to the longitudinal guidance of the motor vehicle in various ways.

[0031] Another exemplary embodiment provides that the driver assistance system is an autonomous emergency braking system and / or an adaptive cruise control system. The autonomous emergency braking system is commonly referred to as autonomous emergency braking (AEB). The adaptive cruise control system may alternatively be referred to as adaptive cruise control (ACC). Thus, preferably, a driver assistance system is provided that is designed to actuated at least one brake of the braking system at least semi-automatically, in particular fully automatically.

[0032] Furthermore, the exemplary embodiment provides that the sensor information is acquired by a sensor device of the motor vehicle. The sensor device is in particular a camera and / or a lidar device. Thus, the sensor device is preferably an imaging sensor that is designed to produce a static and / or moving or dynamic depiction of the environment. For example, in the case of a camera, the sensor information thus includes image data. The sensor device is preferably the front camera of the motor vehicle. Alternatively or additionally, the sensor information may be provided by an external unit, in particular by another motor vehicle, a traffic observation camera and / or a traffic monitoring computing unit, such as a backend, a server and / or a cloud server. The transmission of the sensor information to the motor vehicle may be based on, for example, vehicle-to-vehicle and / or vehicle-to-infrastructure communication.

[0033] Another aspect of the invention relates to a motor vehicle for performing the method described above. Thus, the motor vehicle is designed to perform the method described above. The motor vehicle is, for example, a passenger car, a truck, a bus, a motorcycle and / or a moped. The motor vehicle may have a control device.

[0034] Another aspect of the invention relates to a control device for a motor vehicle, which is designed to perform the method described above. The control device performs the method described, in particular an exemplary embodiment or a combination of exemplary embodiments of the method described. The control device has a processor unit. The processor unit may include at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (field programmable gate array) and / or at least one DSP (digital signal processor). Furthermore, the processor device may have program code, which may also alternatively be referred to as a computer program product. The program code may be stored in the data memory of the processor device.

[0035] Another aspect of the invention relates to a computer program product. The computer program product is a computer program. The computer program product includes instructions that, when the program is executed by a computer, for example by a control device of a motor vehicle, cause the computer to perform the steps of the method according to the invention.

[0036] Exemplary embodiments described in connection with the method according to the invention, whether alone or in combination with each other, are correspondingly applicable to a motor vehicle according to the invention, a control device according to the invention, and a computer program product according to the invention. The invention includes combinations of the described exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the drawings:

[0038] Figure 1 A schematic view of a motor vehicle having a sensor device is shown;

[0039] Figure 2 A schematic view of multiple motor vehicles on a road is shown;

[0040] Figure 3 A schematic view of a signal flow diagram of a method for operating a driver assistance system at least related to the longitudinal guidance of a motor vehicle is shown; and

[0041] Figure 4 A schematic view of a signal flow diagram of further method steps of a method according to Figure 3 is shown. DETAILED DESCRIPTION

[0042] Figure 1 A motor vehicle 1 having a control device 2 is schematically shown. The control device 2 is a computing unit of the motor vehicle 1 and can have, for example, a driver assistance system 3 having at least one function. The driver assistance system 3 is at least related to the longitudinal guidance of the motor vehicle 1. The driver assistance system 3 is, for example, an autonomous emergency braking system and / or an adaptive cruise control system. The functions of the driver assistance system 3 can perform a warning before a predicted collision of the motor vehicle 1 with an obstacle. Alternatively or additionally, the functions of the driver assistance system 3 can perform the braking preparation of at least one brake of the braking system 12 of the motor vehicle 1. Alternatively or additionally, the functions of the driver assistance system 3 can perform braking at least semi-automatically, in particular fully automatically, by at least one brake of the braking system 12.

[0043] The motor vehicle 1 has a sensor device 4. The surroundings of the motor vehicle 1 can be acquired by means of the sensor device 4. As exemplified here, the sensor device 4 can include a plurality of cameras, such as a front camera 5, side cameras 6 and / or a rear camera 7. The sensor device 4 preferably includes at least the front camera 5. Alternatively or additionally, the sensor device 4 can have a lidar device 8, a radar device 9 and / or ultrasonic sensors (not shown here). Here, the side camera 6 is arranged in the side mirror 10 of the motor vehicle 1. The front camera 5 is arranged in a region at the top of the windshield 11 of the motor vehicle 1 along the vertical direction of the motor vehicle 1. A plurality of radar devices 9 and / or lidar devices 8 and / or ultrasonic sensors can be arranged in the motor vehicle 1. Only by way of example, a plurality of such sensors for the front region of the motor vehicle 1 are schematically shown here, and these sensors can be arranged in the bumper of the motor vehicle. By means of these sensors, at least the surroundings of the motor vehicle 1 in the front region of the motor vehicle 1 can be captured.

[0044] An output unit 13 can be arranged in the motor vehicle 1, such as a display screen, in particular a touch-sensitive display screen, a head-up display and / or a speaker unit including at least one speaker. The output unit 13 can be a component of the motor vehicle 1 and / or can be included by a mobile terminal located in the motor vehicle 1. The mobile terminal is, for example, a smartphone and / or a tablet computer. If the function of the driver assistance system 3 provides a warning before a predicted collision, a warning message can be output via the output unit 13.

[0045] Figure 2 A road 14 on which the motor vehicle 1 travels is shown. The road 14 has a right lane 15 and a left lane 16. The same travel direction 18 applies to both lanes 15, 16. In addition to the motor vehicle 1, two other motor vehicles 20 are also located on the road 14, only by way of example here. These vehicles travel on the road 14 in the travel direction 18 in front of the motor vehicle 1. One of the two other motor vehicles 20 travels in the same lane 15, 16 as the motor vehicle 1, that is, in the right lane 15. The other motor vehicle 20 travels in the adjacent left lane 16. Both of the two other motor vehicles 20 have their hazard warning lights activated, that is, all the light units 21 of the corresponding other motor vehicle 20 flash, for example to warn of potential obstacles, such as the end of a traffic jam.

[0046] Figure 3Shows steps of a method for operating a driver assistance system 3, which method at least relates to the longitudinal guidance of a motor vehicle 1. In method step S1, sensor information 22 can be acquired by a sensor device 4. In method step S1, the sensor device 4 preferably comprises at least a front camera 5, and in particular also comprises a side camera 6 and / or a lidar device 8 in addition. The sensor information 22 is provided by a control device 2 in method step S2. The sensor information 22 describes at least one other motor vehicle 20 located in front of the motor vehicle 1 in the travel direction 18 of the motor vehicle 1.

[0047] In method step S3, a hazard warning light detection criterion 23 is applied to the provided sensor information 22. In this way, hazard warning light information 24 is determined, which describes whether at least one other motor vehicle 20 has an activated hazard warning light. In method step S4, it is checked whether it is determined that at least one other motor vehicle 20 has an activated hazard warning light. If this is the case, then in method step S5 a time difference 25 is increased. The time difference 25 describes the time difference at most between the triggering time of the function of the driver assistance system 3 and the predicted collision time of the motor vehicle 1 with an obstacle (in particular another motor vehicle 20). The time difference 25 is increased here by a predetermined time interval 26. In method step S6, taking into account the increased time difference 25, that is, the sum of the original time difference 25 and the predetermined time interval 26, the driver assistance system 3 is then operated.

[0048] It can be provided that the predetermined time interval 26 is first determined, and in this case the inherent speed 27 of the motor vehicle 1 is taken into account. This is determined, for example, in the motor vehicle 1, in particular by means of sensors of the motor vehicle 1 designed for this purpose. Alternatively or additionally, when determining the time interval 26, a relative speed 28 can be taken into account, which describes the relative speed of the motor vehicle 1 with respect to at least one other motor vehicle 20. Thus, the relative speed 28 is the deviation of the inherent speed 27 from the speed of the other motor vehicle 20. The relative speed 28 can be determined, for example, taking into account data of a radar device 9, an ultrasonic sensor and / or a lidar device 8.

[0049] Furthermore, after method step S4, it can be checked in method step S7 whether a plurality of other motor vehicles 20 have an activated hazard warning light. Here, three other motor vehicles 20 are schematically shown by way of example, which are traveling or parked with an activated hazard warning light. Thus, distance information 29 is determined for each of the plurality of other motor vehicles 20. This takes place in method step S8. The corresponding distance information 29 describes the distance between the motor vehicle 1 and the other motor vehicle 20. In this case, only other motor vehicles 20 with an activated hazard warning light are taken into account. Thus, three distance information items 29 are determined in the example outlined here.

[0050] Then, the minimum distance information item 30 is selected from the determined distance information items 29. Accordingly, the relative speed 28 of the motor vehicle 1 with respect to the other motor vehicle 20 that is selected and determined to have the minimum distance information item 30 relative to the motor vehicle 1 is considered. Accordingly, it can be stipulated that when determining the predetermined time interval 26, the determined minimum distance information item 30 is considered.

[0051] Instead of considering all the other motor vehicles 20 described by the sensor information 22, it can be stipulated in method step S10 which of the other motor vehicles 20 with activated hazard warning lights is located in the same lanes 15, 16 as the motor vehicle 1 after method step S7. This is exactly one other motor vehicle 20 here, which is schematically shown here as the determined other motor vehicle 31 for example. Only for the determined other motor vehicle 31, in method step S11, the distance information 29 describing the distance between the motor vehicle 1 and the determined other motor vehicle 31 is determined. If multiple determined other motor vehicles 31 are determined, the relative speed 28 of the motor vehicle 1 with respect to the other motor vehicle 31 for which the minimum distance information 30 is determined relative to it is considered, that is, method step S9 is carried out.

[0052] However, in method steps S8 and S9, in principle, any other motor vehicle 20 can be considered without method steps S10 and S11, even if for example it is located in the adjacent lanes 15, 16 of the lanes 15, 16 of the motor vehicle 1. Refer to Figure 2 , and thus the relative speed 28 with respect to the other motor vehicle 20 traveling in the left lane 16 can be considered because this vehicle is at a smaller distance from the motor vehicle 1 than the other motor vehicle 20 traveling directly in front of the motor vehicle 1 in the right lane 15. However, in method steps S10, S11 and then S9, this other motor vehicle 20 is not considered at all, but only the other motor vehicle 20 traveling directly forward and thus also in the right lane 15 is considered.

[0053] Furthermore, it can be stipulated that the hazard warning light information 24 is continuously checked. Once it is determined according to the determined hazard warning light information 24 that no other motor vehicle 20 still has an activated hazard warning light, the time difference 25 is again reduced by the predetermined time interval 26. The driver assistance system 3 then operates again taking into account the reduced time difference 25 and thus taking into account the original time difference 25.

[0054] It can be stipulated that if in method step S4 it is determined that according to the determined hazard warning light information 24 no other motor vehicle 20 with an activated hazard warning light is established, method step S1 can be directly carried out again.

[0055] Furthermore, method step S12 can be provided, in which it is checked whether the driver assistance system 3 is currently operating according to the increased time difference 25. If this is the case, in method step S13, the time difference 25 can again reduce the time interval 26. If it is determined in the check that the current driver assistance system 3 is not operating at all with the increased time difference 25, method step S1 is likewise executed again. If, for example, it is determined in method step S7 that the hazard warning lights of a plurality of other motor vehicles 20 are not activated at all, method step S5 can be carried out.

[0056] Figure 4 Two optional method steps S14 and S15 are schematically shown. In method step S14, it is checked whether the intrinsic speed 27 of the motor vehicle 1 is greater than a predetermined speed difference 32. The speed difference 32 is permanently predetermined for the driver assistance system 3. It describes the speed difference by which the intrinsic speed 27 of the motor vehicle 1 can be reduced at most with the aid of the driver assistance system 3. Thus, the situation described here is that the driver assistance system 3 cannot decelerate from any arbitrary intrinsic speed 27 to a standstill, but only, for example, decelerates by a speed difference of, for example, 60 km / h. If this is the case, then in method step S15, the time difference 25 is increased by a predetermined further time interval 26', which is greater than the predetermined time interval 26. For the predetermined further time interval 26', at least one reaction time 33 for the reaction of the driver of the motor vehicle 1 is taken into account. For this purpose, the reaction time 33 can be specifically pre-determined by the driver. If the intrinsic speed 27 is less than or equal to the speed difference 32, the method can end or method step S5 can be carried out. Thus, method step S14 can be executed after method step S4 or S7, and method step S15 replaces method step S5. After method step S15, method step S6 is preferably executed, taking into account the time difference 25 increased by the predetermined further time interval 26'.

[0057] Overall, these examples show the adjustment of the time difference threshold by detecting the hazard warning light system of other motor vehicles 20 ahead. The ego vehicle (motor vehicle 1) uses an optical sensor such as the front camera 5 or the lidar device 8 to detect the hazard warning light system of other motor vehicles 20 ahead. The motor vehicle 1 increases the time difference 25 (TTC threshold) of the driver assistance system 3 (for example for FCW (Forward Collision Warning), pre-fill and braking). This increase can occur dynamically depending on the intrinsic speed 27 and / or the relative speed 28 with respect to the most critical other motor vehicle 20.

[0058] On a highway, a motor vehicle 1 is traveling at 120 km / h. Ahead of it, a number of other motor vehicles 20 have their hazard warning light systems switched on and are not moving, indicating a traffic jam. A typical driver assistance system configuration has a time difference 25 (TTC threshold) of 1.4 seconds. In this case of the inherent speed 27 and relative speed 28 and with a typical deceleration of 9 m / s per second on a dry road surface, this causes the motor vehicle 1 to brake when it is at a distance of 46.66 m from the other motor vehicles 20 ahead. However, in order for the motor vehicle 1 to stop without a collision, 61.67 m is required, meaning that a collision cannot be avoided here. However, if the time difference 25 (TTC threshold) is increased to 1.9 seconds (an increase of 0.5 seconds), the motor vehicle 1 brakes when it is still at a distance of 63.33 m from the other motor vehicles 20 ahead and stops at a distance of 1.66 m. Thus, a collision is avoided here.

Claims

1. A method for operating a driver assistance system (3), the method being at least related to the longitudinal guidance of a motor vehicle (1), comprising: - providing (S2) sensor information (22) that describes at least one other motor vehicle (20) located in front of the motor vehicle (1) in the travel direction (18) of the motor vehicle (1); - determining (S3) hazard warning light information (24) by applying a hazard warning light detection criterion (23) to the provided sensor information (22), the hazard warning light information (24) describing whether the at least one other motor vehicle (20) has an activated hazard warning light; - if, according to the determined hazard warning light information (24), the at least one other motor vehicle (20) has an activated hazard warning light, increasing (S5) a time difference (25) by a predetermined time interval (26), the time difference (25) describing the time difference between at most the trigger time of the function of the driver assistance system (3) and the collision time of a predicted collision between the motor vehicle (1) and an obstacle around the motor vehicle (1); and - operating (S6) the driver assistance system (3) taking into account the increased time difference (25).

2. The method according to claim 1, wherein, The predetermined time interval (26) is determined taking into account at least the inherent speed (27) of the motor vehicle (1).

3. The method according to claim 1 or 2, wherein The predetermined time interval (26) is determined taking into account at least the relative speed (28) of the motor vehicle (1) with respect to the at least one other motor vehicle (20).

4. The method according to claim 3, wherein, If a plurality of other motor vehicles (20) have activated hazard warning lights, a distance information item (29) is determined (S8) for each of the plurality of other motor vehicles (20), the distance information item (29) describing the distance between the motor vehicle (1) and the other motor vehicle (20), and the relative speed (28) of the motor vehicle (1) with respect to the other motor vehicle (20) that is determined to have the smallest distance information item (30) relative thereto is taken into account.

5. The method according to claim 3, wherein If a plurality of other motor vehicles (20) have activated hazard warning lights, it is determined (S10) which of these other motor vehicles (20) are located in the same lane (15, 16) as the motor vehicle (1); a distance information item (29) describing the distance between the motor vehicle (1) and the determined other motor vehicle (31) is determined (S11) only for the respective determined other motor vehicle (31), and the relative speed (28) of the motor vehicle (1) with respect to that other motor vehicle (31) which is determined to have the smallest distance information item (30) relative to the motor vehicle (1) is taken into account.

6. The method according to any one of claims 4 or 5, wherein The predetermined time interval (26) is determined taking into account at least the determined smallest distance information item (30).

7. The method according to any one of the preceding claims referring to claim 2, wherein, Check (S14) whether the inherent speed (27) of the motor vehicle (1) is greater than a predetermined speed difference (32), which is predetermined for the driver assistance system (3) and describes the speed difference by which the inherent speed (27) can be reduced at most by means of the driver assistance system (3), wherein if the inherent speed (27) is greater than the predetermined speed difference (32), the time difference (25) is increased (S15) by a predetermined other time interval (26'), which is greater than the predetermined time interval (26).

8. The method according to claim 7, wherein, Determine the predetermined other time interval (26') taking into account at least the reaction time of the driver of the motor vehicle (1).

9. The method according to any one of the preceding claims, wherein, Continuously determine and check the hazard warning light information (24), wherein once it is determined based on the determined hazard warning light information (24) that no other motor vehicle (20) has an activated hazard warning light, the time difference (25) is again decreased by the predetermined time interval (26), and the driver assistance system (3) is operated again (S13) taking into account the decreased time difference (25).

10. The method according to any one of the preceding claims, wherein, The functions of the driver assistance system (3) include a warning of a predicted collision, the preparation of at least one brake of the braking system (12) of the motor vehicle (1) and / or braking by means of the at least one brake.

11. The method according to any one of the preceding claims, wherein, The driver assistance system (3) is an autonomous emergency braking system and / or an adaptive cruise control system.

12. The method according to any one of the preceding claims, wherein, Capture the sensor information (22) by means of the sensor device (4) of the motor vehicle (1), in particular by means of a camera and / or a lidar device as the sensor device (4).

13. A motor vehicle (1) designed to perform the method according to any one of the preceding claims.

14. A control device (2) for a motor vehicle (1), designed to perform the steps provided for the control device (2) of the method according to any one of claims 1 to 12.

15. A computer program product comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 12.

Images