Method for operating driver assistance system of vehicle, driver assistance system and motor vehicle having driver assistance system

Abstract

The invention relates to a method for operating a driver assistance system (12) of a motor vehicle (10), in which the driver assistance system (12) triggers a predetermined safety measure of the motor vehicle (10) when a predetermined warning threshold is reached during a journey of the motor vehicle (10). According to the invention, a first trigger event is detected, said first trigger event comprising a first trigger of a predetermined safety measure within a first travel section of the travel. A response and / or a response speed of a driver of the motor vehicle (10) to the first trigger event is then observed. The attention value of the driver is then adjusted as a function of the observed reaction and / or the observed reaction speed. Finally, the warning threshold is adjusted as a function of the adjusted attention value.

Description

Field of the Invention

[0001] The present invention relates to a method for operating a driver assistance system of a motor vehicle, wherein, during a journey of the motor vehicle, when a predetermined warning threshold is reached, the driver assistance system triggers a predetermined safety measure of the motor vehicle. The present invention also relates to such a driver assistance system and a motor vehicle having such a driver assistance system. Background Art

[0002] It is well known that insufficient or reduced attention levels of a driver of a motor vehicle in road traffic can lead to an increase in accidents, such as collisions. Therefore, many motor vehicles are equipped with driver assistance systems that can independently intervene in the current driving operation of the motor vehicle, for example, independently trigger the braking of the motor vehicle (AEB - Autonomous Emergency Braking) in the case of insufficient driver attention. Before such an automatically triggered braking of the motor vehicle, a corresponding collision warning (FCW - Forward Collision Warning) is usually output by the driver assistance system. To trigger the braking and / or the previous warning, thresholds or warning thresholds can be specified, where if the associated warning threshold is exceeded, the corresponding measure is triggered. Such a warning threshold can describe the remaining time before an upcoming collision (e.g., in seconds) (TTC - Time To Collision). The corresponding warning threshold can be referred to as a TTC threshold.

[0003] It is known from DE 10 2015 117 976 A1 to adapt the TTC threshold to the current driving speed of the motor vehicle and / or the current relative speed of the motor vehicle with respect to a potential collision obstacle. For this purpose, the current driving speeds of the motor vehicle and other road users must be detected and processed in a complex manner.

[0004] It is known from CN 11 20 46 454 A to adapt the TTC threshold according to current environmental conditions (such as road gradient and / or icy road). In other words, if a steep road and / or a slippery road surface result in an increased or extended braking distance, the warning threshold can be adjusted upwards here. To implement the described method, the current data regarding the road layout, road condition, and / or current weather condition must be retained and processed, which is also very complex.

[0005] Another known possibility for reducing the likelihood of accidents in road traffic due to insufficient driver attention in a motor vehicle is to continuously monitor the driver's current attention by means of sensors inside the motor vehicle, such as camera sensors, and, if a reduced attention level is determined, to accordingly warn the driver (DMS driver monitoring system). Thus, in the current driving operation of the vehicle, no automatic or autonomous intervention of the system takes place here, but rather the driver is supposed to restore the increased attention level due to the warning. However, disadvantageously, such monitoring systems are complex to install because they rely on a large number of sensors. These sensors detect and process a large amount of data, which makes the implementation of such systems in a motor vehicle environment complex. In addition, such monitoring systems are unreliable. This is because if the light conditions inside the motor vehicle are poor, for example in certain situations, the camera sensors cannot reliably detect a decrease in the driver's attention.

[0006] Even if the driver is warned by the DMS that his attention is decreasing, he can ignore the warning and continue to participate in road traffic despite his insufficient attention. Thus, the driver observation system only increases overall traffic safety to a limited extent. Summary of the Invention

[0007] An object of the present invention is to provide an effective and reliable possibility for increasing overall traffic safety.

[0008] This object is achieved by the subject matter of the independent claims. Advantageous refinements of the invention are described in the dependent claims, the following description and the drawings.

[0009] The present invention is based on the finding that during the journey of a motor vehicle, the scope and / or frequency of the above-mentioned interventions of driver assistance functions, such as triggering FCW or AEB, allows an inference of the current attention of the motor vehicle driver.

[0010] The present invention provides a method for operating a driver assistance system of a motor vehicle, wherein during the journey of the motor vehicle, when a predetermined warning threshold is reached, the driver assistance system triggers a predetermined safety measure for the motor vehicle. The warning threshold can be the above-mentioned TTC warning threshold. The predetermined safety measure can for example be outputting a collision warning and / or intervening in the autonomous braking function of the motor vehicle. For example, if the warning threshold is preset to 3 seconds, the safety measure is triggered as soon as the driver assistance system recognizes that without taking safety measures, a collision of the motor vehicle with an external object is expected within 3 seconds. A typical warning threshold for intervening in the autonomous braking function can be 1.3 seconds.

[0011] According to the present invention, such a trigger is detected as a trigger event, wherein the first trigger event includes a first trigger of a predetermined safety measure within a first travel section of the travel. In addition, the reaction and / or reaction speed of the driver of the motor vehicle to the first trigger event are observed. For example, when the driver performs a braking process of the motor vehicle in response to the output collision warning, it can be recognized by the brake pedal sensor of the motor vehicle. In this case, not only can it be detected whether such a reaction occurs, but also at what time. In other words, it can be detected whether the driver reacts with a braking operation immediately after triggering the collision warning, or only when the motor vehicle has been autonomously braked.

[0012] According to the present invention, the attention value of the driver is adjusted according to the observed reaction and / or the observed reaction speed. For example, if no reaction to the triggered safety measure is observed, the attention value can thus be set from the initial value of 1 to 0. If a reaction is recognized immediately after triggering the collision warning, the attention value can be reduced to a value greater than zero, for example 0.8. If no reaction is made to the triggered collision warning, but only during the automatic braking process after the warning, the attention value can be set to 0.4. If the driver does not brake immediately for this reason, but only when the autonomous braking system has been used or triggered, the attention value is reduced more severely compared to when the driver has reacted to the collision warning through a braking process. The values mentioned here are merely exemplary and should not be construed as restrictive.

[0013] According to the present invention, the warning threshold is adjusted according to the adjusted attention value. Therefore, in the case where the attention value is reduced, the warning threshold can be increased, so that when preparing for the recognized upcoming collision, the predetermined safety measure for the motor vehicle is triggered far enough in advance, so that the inattentive driver has more time to react.

[0014] The advantage of the method according to the present invention is that the existing vehicle functions are used to determine the attention value of the driver. This results in particularly effective attention monitoring. At the same time, the determination of the attention value according to the present invention is particularly reliable. Therefore, the warning threshold can also be adjusted very reliably. Therefore, the present invention advantageously enhances the overall traffic safety.

[0015] The present invention also includes embodiments that produce additional advantages.

[0016] One embodiment provides that if at least one additional triggering event is detected during an additional subsequent journey segment during the further course of the journey, the reaction and / or reaction speed of the driver to the at least one additional triggering event is observed, and the adjusted attention value of the driver is updated based on the observed reaction and / or observed reaction speed to the at least one additional triggering event, and wherein the adjusted warning threshold is adjusted again according to the updated attention value. In other words, according to the embodiments described herein, during the further course of the journey, the warning threshold is dynamically adjusted to the changing attention value. In other words, the reactions of the driver to multiple consecutive triggering events can be accumulated, wherein the gradually updated attention value of the driver is determined from the accumulated reactions. For example, multiple consecutive triggering events and the subsequent observed reactions and / or reaction speeds of the driver can be accumulated until a critical limit value is reached. When the limit value is reached, the warning threshold can be increased by a defined increment or by a defined step size, for example by one second.

[0017] The embodiments described herein can be based on the situation that at the start of the journey of a motor vehicle, the attention value of the driver is 100%. If a first triggering event occurs, for example, after a journey duration of 70 minutes, thus triggering a warning about an impending collision, for example, and the driver reacts to this warning with a braking operation, so that the automatic braking is not caused by the motor vehicle, then 5% can be subtracted from the initially 100% attention value. Thus, the attention value after 70 minutes of the journey is 95%.

[0018] During the further course of the journey, for example, after 75 minutes, an additional triggering event can occur. In this case, a collision warning can initially be output again, wherein the driver does not brake in time during the additional triggering event. Therefore, the autonomous braking system of the motor vehicle intervenes. For example, if the driver only delays braking and the autonomous braking system is still braking, 15% is subtracted from the attention value. In this example, after 75 minutes of driving time, the attention value is thus 80%.

[0019] During the further course of the journey, for example, after 80 minutes, a third triggering event can occur. For example, during this triggering event, the driver no longer has any reaction. In other words, a collision warning is initially output, followed by the autonomous braking process of the motor vehicle. No reaction of the driver to the collision warning or during the automatic braking process is observed. In this example, 20% can be subtracted from the attention value. Thus, after 80 minutes of the journey, the attention value is still only 60%.

[0020] For example, the first limit value of the attention value is 75%. Based on exceeding this first limit value, one second can be added to the warning threshold. Here, a distinction can be made between the warning threshold for triggering a collision warning and the warning threshold for an automatically executed braking process. For example, due to the increased warning threshold, when an upcoming collision will occur not within 10 seconds but within 11 seconds, the collision warning can already be triggered as a predefined safety measure. At the same time, the triggering of an automatic braking process can be defined as a safety measure, i.e., it already starts when a collision is about to occur within five and a half seconds, rather than just within five seconds. These examples show that with the increase of the warning threshold, the predefined safety measures for a motor vehicle are triggered earlier, so that the driver of the motor vehicle has more time to react. The advantage of dynamically adjusting the warning threshold during a journey in this way is that it can flexibly respond to the driver's current attention or current attention value.

[0021] Another embodiment provides that when adjusting the attention value and / or the warning threshold, the time interval between consecutive triggering events during the journey and / or the frequency of triggering events during the journey are considered. For example, if a particularly large number of triggering events occur within a short period of time, such as more than 10 triggering events within less than 10 minutes, additional factors can be considered when reducing the attention value and / or increasing the warning threshold.

[0022] Another embodiment provides that after a predefined journey duration of the journey, the attention value of the driver is updated at a predefined time point, where the last triggering event and the observed driver's reaction and / or reaction speed to it at this time point are discarded, and the warning threshold is adjusted again according to the attention value updated at this time point. In other words, the last triggering event is no longer considered when adjusting the warning threshold. In other words, the driver can increase his attention value again during the journey.

[0023] For the above example, this may mean that, for example, after 100 minutes of journey time, the initially subtracted 5% is added to the attention value again. The attention value after 100 minutes is accordingly 65% again.

[0024] The triggering events are preferably finally discarded when the current journey ends. In other words, the driver can start again with the original attention value of 100% in the next journey. The advantage of this is that when the driver's attention increases again, an unnecessarily long warning duration is not selected.

[0025] Another embodiment provides that the predefined safety measures include successive individual measures, where the individual measures are classified based on predefined measure categories. In the embodiments described herein, the adjustment of the attention value and / or the warning threshold occurs depending on during which process of the successive individual measures the driver's reaction occurs. To maintain the above example, the driver's reaction may have occurred, for example, during the output of a collision warning. Compared to the driver intervening first during the subsequent autonomous braking operation of the motor vehicle, this results in a smaller decrease in the attention value. In this way, it advantageously results in an increased granularity in the adjustment of the attention value and thus also in the adjustment of the warning threshold.

[0026] Another embodiment provides that the predefined safety measures include outputting a warning to the driver of the motor vehicle, in particular a collision warning regarding an impending collision, and / or a subsequent intervention by at least one autonomous safety system, such as the autonomous braking system of the motor vehicle. In other words, the safety measures preferably include an intervention by the autonomous safety system of the motor vehicle, in particular the autonomous execution of a braking process.

[0027] The driver's reaction preferably includes a steering intervention and / or a braking process.

[0028] Another embodiment provides that data is obtained from a driver monitoring system (DMS) and additionally considered for adjusting the driver's attention value and / or for adjusting the warning threshold. In other words, the DMS can determine its own attention value, for example based on the monitoring of the driver by a camera. The attention values of the DMS and the driver assistance system described herein can be offset from each other to form a common attention value. It can be preferably provided that the DMS attention value is classified as less reliable than the attention value obtained from the observation of the driver's reaction according to the present invention. In other words, the DMS attention value can be overridden. The advantage of this is to reduce the technical requirements for the DMS. Therefore, it does not have to be equipped with a large number of sensors in a complex manner.

[0029] Furthermore, the present invention relates to a driver assistance system for a motor vehicle, wherein the driver assistance system is designed to perform the method. The driver assistance system includes a sensor device or sensor system having a plurality of sensors and a controller to perform the method according to the present invention. The driver assistance system can include or actuate an environment sensor or an environment sensor system, in particular a plurality of sensors of the sensor system, to obtain environmental data of the motor vehicle. The environment sensor system can be understood as, for example, a sensor system capable of generating sensor data or sensor signals that depict, represent, or reflect the environment of the environment sensor system. In particular, the ability to obtain electromagnetic or other signals from the environment is not sufficient to consider the sensor system as an environment sensor system. For example, a camera, a radar system, a lidar system, or an ultrasonic sensor system can be interpreted as an environment sensor system.

[0030] A sensor system can include, for example, sensors with which an impending collision and / or the time until such a collision can be detected. These sensors can in particular be cameras, radar systems, lidar systems or ultrasonic sensor systems.

[0031] Furthermore, the sensor system can include sensors with which the movement of the motor vehicle can be detected, or sensors which can detect variables associated with the movement of the motor vehicle. These sensors can include, for example, an IMU (inertial measurement unit) which measures the acceleration and / or the rate of rotation, such as the yaw rate, of the motor vehicle in one or more directions. These sensors can also include wheel sensors which measure the number of revolutions of the wheels of the motor vehicle, based on which the speed of the motor vehicle can be calculated. Furthermore, these sensors can also include a steering wheel / steering column sensor which measures the angle and / or the angular velocity of the steering wheel or a rotation or partial rotation of the steering wheel.

[0032] Furthermore, the driver assistance system can include an electronic controller by means of which triggering events and / or the corresponding reaction or reaction speed of the motor vehicle driver to the triggering events can be recorded or detected. The steering system, the drive motor and / or the braking system of the motor vehicle can also be actuated by the controller.

[0033] The invention also relates to a computer program comprising commands which, when executed by a driver assistance system according to the invention, cause the driver assistance system according to the invention to carry out the method steps of the method according to the invention.

[0034] The invention also relates to a computer-readable storage medium on which a computer program is stored.

[0035] The invention also relates to a motor vehicle having a driver assistance system according to the invention. The motor vehicle is preferably designed as a passenger car, truck, bus, motorcycle or moped.

[0036] The preferred embodiments and their advantages described with regard to the method according to the invention apply correspondingly to the driver assistance system according to the invention and to the motor vehicle according to the invention, and vice versa.

[0037] Other features of the present invention can be found in the claims, the drawings and the description of the drawings. Without departing from the scope of the present invention, the features and combinations of features mentioned in the above description and the features and combinations of features mentioned in the following description of the drawings and / or shown separately in the drawings can be used not only in the separately indicated combinations, but also in other combinations. Therefore, embodiments of the present invention that are not explicitly shown and explained in the drawings, but that arise and result from the separately explained embodiments by means of combinations of individual features, should also be considered to be included and disclosed. Therefore, embodiments and combinations of features that do not have all the features of the initially formulated independent claims should also be considered to be disclosed. In addition, embodiments and combinations of features that go beyond or deviate from the combinations of features outlined in the back-reference of the claims should be considered to be disclosed, in particular by the above-described embodiments. Description of the Drawings

[0038] Exemplary embodiments of the present invention are described below. In the drawings:

[0039] Figure 1 A motor vehicle with a driver assistance system is shown;

[0040] Figure 2 A schematic diagram of a method according to an embodiment of the present invention is shown. Detailed Description of the Invention

[0041] The exemplary embodiments explained below are preferred embodiments of the present invention. In the exemplary embodiments, the described components of the embodiments each represent separate features of the present invention that are considered to be independent of one another, and these features each also complete the present invention independently of one another, and will therefore also be considered to be part of the present invention either individually or in combinations other than those shown. In addition, the described embodiments can also be supplemented by other features of the present invention that have already been described.

[0042] In the drawings, the same reference numerals each denote elements having the same function.

[0043] Figure 1The figure shows a schematic view of a motor vehicle 10 including a driver assistance system 12. The motor vehicle 10 is designed as a passenger car in the illustrated embodiment. The motor vehicle 10 includes a plurality of sensors 14 of a sensor device (not described in detail). These sensors 14 include, for example, camera sensors and / or distance sensors according to the exemplary embodiments described herein, and they can be arranged in different areas of the motor vehicle 10. In addition, the sensor device includes one or more sensors 16, which can be designed, for example, to detect the movement of the motor vehicle 10 or to detect variables related to or affecting the movement of the motor vehicle 10. For example, using the sensor 16, the steering angle and / or the number of revolutions of at least one wheel of the motor vehicle 10 can be determined. The sensor 16 can be designed to detect the current speed and / or one or more accelerations and / or rotational speeds of the motor vehicle 10. This can also include detecting a braking process, especially an autonomously executed braking process. The motor vehicle 10 can also include additional sensors 14, such as a brake pedal sensor and / or a camera sensor for monitoring the driver inside the motor vehicle.

[0044] The sensors 14, 16 can be connected to a controller 18 of the driver assistance system 12 for data transmission.

[0045] With reference to the components Figure 1 represented and described, Figure 2 The figure shows a schematic view of a method for operating the driver assistance system 12 of the motor vehicle 10. In this method, when a predetermined warning threshold is reached during the journey of the motor vehicle 10, the driver assistance system 12 triggers a predetermined safety measure for the motor vehicle 10.

[0046] In step S1, a first trigger event is detected, where the first trigger event includes a first trigger of a predetermined safety measure within a first journey section of the journey. In step S2, the reaction and / or reaction speed of the driver of the motor vehicle 10 to the first trigger event is observed. In step S3, the attention value of the driver is adjusted or updated according to the observed reaction and / or the observed reaction speed. Finally, in step S4, the warning threshold is adjusted or updated according to the adjusted attention value.

[0047] A preferred embodiment of the present invention provides for dynamically adjusting the warning threshold during the journey of the motor vehicle 10. Here, the adjustment can be made according to the scope and / or frequency of the trigger events observed during the journey or during a predetermined journey section.

[0048] For example, the driver assistance system 12 stores the described trigger events during a previous time span or a previous journey section, and evaluates the driver's attention based on the trigger events. The trigger events can be described here by a timestamp, the type of the triggered safety measure, and / or the driver's reaction.

[0049] At the start of a journey, for example when starting the vehicle motor, the driver's attention value can be 100%. Warning thresholds for different safety measures can be preset at the start of the journey. For example, the presetting can be set by the factory or can also be determined by the driver's choice. If now the first safety measure is triggered, for example an output of a warning about an impending collision, and at the same time the driver's braking process and / or steering process is detected, so that no automatic braking process is triggered, a small part is subtracted from the driver's current attention value. If the driver's braking process or steering process is not sufficient to prevent the intervention of the automatic braking function, a larger part is subtracted from the current attention value. If the driver brakes and / or the driver steers while the automatic braking function has already intervened, an even larger part is subtracted from the current attention value. If the driver does not react, or only reacts after the motor vehicle has autonomously stopped, an even larger part is subtracted from the attention value. If the attention value drops below a predetermined limit value, for example below 50% of the starting value, the warning thresholds for different safety measures can be increased. There can be different limit values here. For example, a further limit value can be 25% of the starting value of 100%. Preferably, the lower the correspondingly reached limit value, the greater the warning threshold.

[0050] If one of the recorded trigger events lies further back than a predetermined time section, the contribution of this trigger event can be discarded or waived in the adjustment of the attention value. This means that the part subtracted from the attention value according to this trigger event can be added again. The trigger event can be erased or overwritten by a newly recorded trigger event. This mechanism can prevent the deduction of the attention value from accumulating over an indefinite period of time. Thus, it can be prevented that the driver's attention value continuously decreases, which could lead to an unnecessary increase in the warning threshold and / or an unnecessary premature triggering of safety measures.

[0051] If the motor vehicle 10 is not equipped with an additional driver monitoring system or the like for evaluating the driver's attention, the described solution can function alone. Alternatively, the proposed solution can also function in conjunction with an existing driver observation system or a similar mechanism. For example, if the DMS reports an increase in the driver's attention, the attention value described here can also increase. If one or more trigger events are detected, the DMS can thus also reduce its driver attention value.

[0052] The invention provides a simple, reliable and effective solution for adjusting warning thresholds as required. For this purpose, the functions of driver assistance functions already present in the motor vehicle or of ADAS (ADAS - Advanced Driver Assistance Systems) can be used.

Claims

1. A method for operating a driver assistance system (12) of a motor vehicle (10), wherein, the driver assistance system (12) includes a sensor system having a plurality of sensors (14, 16) and a controller (18), and if a predetermined warning threshold is reached during the travel of the motor vehicle (10), a predetermined safety measure for the motor vehicle (10) is triggered by the driver assistance system (12), the method includes the following steps: - Detecting (S1) a first trigger event by at least one sensor (14, 16) of the sensor system, wherein the first trigger event includes a first trigger of a predetermined safety measure within a first travel section of the travel, - Observing (S2) the reaction and / or reaction speed of the driver of the motor vehicle (10) to the first trigger event by at least one additional sensor (14, 16) of the sensor system, - Adjusting (S3) the attention value of the driver by the controller (18) according to the observed reaction and / or the observed reaction speed, - Adjusting (S4) the warning threshold by the controller (18) according to the adjusted attention value.

2. The method according to claim 1, wherein, if at least one additional trigger event is detected during an additional subsequent travel section during the additional travel of the travel, the reaction and / or reaction speed of the driver to the at least one additional trigger event is observed, and the adjusted attention value of the driver is updated based on the observed reaction and / or the observed reaction speed to the at least one additional trigger event, and wherein the adjusted warning threshold is adjusted again according to the updated attention value.

3. The method according to claim 2, wherein, when adjusting the attention value and / or the warning threshold, the time interval between consecutive trigger events during the travel and / or the frequency of trigger events during the travel are considered.

4. The method according to any one of the preceding claims, wherein, after a predetermined travel duration of the travel, the attention value of the driver is updated at a predetermined time point, wherein the last trigger event and the observed reaction and / or reaction speed of the driver to the trigger event at that time point are discarded, and in particular, the warning threshold is adjusted again according to the attention value updated at that time point.

5. The method according to any one of the preceding claims, wherein, the predetermined safety measure includes consecutive individual measures, wherein the individual measures are classified based on a predetermined measure category, and wherein the adjustment of the attention value and / or the warning threshold occurs depending on which process of the consecutive individual measures the driver's reaction occurs in.

6. The method according to any one of the preceding claims, wherein, The predetermined safety measures include outputting a warning to the driver of the motor vehicle (10), in particular a collision warning regarding an impending collision of the motor vehicle (10) with an external object of the motor vehicle, and / or an intervention of at least one autonomous safety system of the motor vehicle (10) in the current operation of the motor vehicle (10).

7. The method according to claim 6, wherein, the intervention of the at least one autonomous safety system of the motor vehicle includes the autonomous execution of a braking process.

8. The method according to any one of the preceding claims, wherein, the reaction of the driver includes a steering intervention and / or a braking process.

9. The method according to any one of the preceding claims, wherein, data is obtained from a driver monitoring system, and wherein the data is additionally considered for adjusting the attention value of the driver and / or for adjusting the warning threshold.

10. A driver assistance system (12) comprising a sensor system having a plurality of sensors (14, 16) and a controller (18), wherein, the driver assistance system (12) is designed to trigger predetermined safety measures for the motor vehicle (10) if a predetermined warning threshold is reached during the travel of the motor vehicle (10), wherein, - at least one sensor (14, 16) of the sensor system is designed to detect a first triggering event, wherein the first triggering event includes a first triggering of the predetermined safety measures within a first travel section of the travel, - at least one further sensor (14, 16) of the sensor system is designed to observe the reaction and / or reaction speed of the driver of the motor vehicle (10) to the first triggering event, - the control unit (18) is designed to adjust the attention value of the driver according to the observed reaction and / or the observed reaction speed, and wherein, - the control unit (18) is designed to adjust the warning threshold according to the adjusted attention value.

11. A motor vehicle (10) having a driver assistance system (12) according to claim 10.

12. A computer program comprising instructions which, when executed by a driver assistance system (12) according to claim 10, cause the driver assistance system (12) according to claim 10 to perform the method steps according to any one of claims 1 to 9.

13. A computer-readable storage medium having stored thereon the computer program according to claim 12.

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