Method and driver assistance system for detecting fatigue and / or assessing driver attention

Abstract

The invention relates to a method and a driver assistance system for fatigue detection and / or attention assessment of a driver of a vehicle, in particular for detecting impending or onset microsleep, wherein a distance and / or a relative speed to a vehicle in front are taken into account in the fatigue detection and / or attention assessment, wherein a temporal course of a change in the distance to the vehicle in front is taken into account, wherein the distance is determined by means of a distance radar, and / or by means of a stereo camera for distance determination, and / or by means of another device, and the information on distance and relative speed is determined alternatively or additionally via a vehicle-to-vehicle or vehicle-to-infrastructure communication device, where Depending on the attention assessment and / or fatigue detection carried out within the procedure, safety-relevant measures are triggered, whereby multi-stage intervention strategies are defined and / or several threshold values ​​are defined in such a way that when a first threshold value is reached, an acoustic warning is issued to the driver of the vehicle, when a second threshold value is reached, measures are pre-coordinated and when a third threshold value is reached, the measures are triggered, whereby a shortfall of a target distance to the vehicle in front is taken into account and a percentage shortfall of the target distance is taken into account.

Description

[0001] The invention relates to a method and a driver assistance system for detecting fatigue and / or assessing the attention level of a driver of a vehicle, in particular for detecting impending or onset microsleep.

[0002] In modern vehicles, such as passenger cars, trucks, and motorcycles, so-called driver assistance systems are increasingly being used, particularly with safety-relevant functions. Such systems include, for example, environmental detection systems for the early detection of hazards or dangerous situations and for the preconditioning or triggering of safety functions in the vehicle, for example, occupant protection systems such as airbags and seat belt tensioners or (emergency) braking assistants.

[0003] Due to increasing traffic density, it is becoming increasingly important for vehicle drivers to drive their vehicles as accurately and accurately as possible with a high level of concentration. However, since many drivers generally only recognize their own fatigue or reduced attention, and the associated reduced reaction time, with difficulty or too late, vehicles, especially those used in heavy goods vehicles, will in future be equipped with assistance systems for fatigue detection and / or attention assessment, or with systems for determining reaction times.

[0004] Such systems are known, for example, from DE 10 2004 034 748 A1, DE 10 2005 017 242 A1 and DE 10 2004 036 119 B4.

[0005] DE 10 2004 034 748 A1 describes a driver assistance system for detecting fatigue and / or assessing the attention level of a vehicle driver, comprising an evaluation unit, a road monitoring system in the form of an optical detection system acting in the direction of travel, suitable for detecting the course of the road, a human-machine interface in the form of a steering wheel for controlling the direction of travel, a steering mechanism for aligning one or more steerable wheel(s) and for setting the desired direction of travel, as well as an activatable warning device, wherein the warning device is activated depending on how strongly, how long and / or how often the set direction of travel and / or the actual lane usage and the actual road course and / or the target lane usage to be maintained deviate from one another.

[0006] DE 10 2005 017 242 A1 shows a similar system to DE 10 2004 034 748 A1, wherein the driver assistance system additionally comprises a speed detection system and / or an interface for receiving vehicle speed information, and wherein the intervention limit for activating the warning device is varied as a function of the vehicle's own speed and the available lane width and / or is dependent thereon.

[0007] In contrast, DE 10 2004 036 119 B4 discloses a driver assistance system for detecting fatigue and / or assessing driver alertness, comprising a sensor and / or a sensor arrangement suitable for detecting the driver's pulse rate. The driver's pulse rate is continuously monitored so that, in the event of a sudden change in the pulse rate by a predetermined value, the warning device can be activated, and / or to be able to record or initiate documentation in a storage device, at least in the event of an unusual vehicle event that can be linked to the period of the pulse rate change.

[0008] EP 1 721 800 A2 discloses a device for detecting the driver’s condition, an alarm system in the vehicle and a driver assistance system.

[0009] JP 2002 - 219 968 A shows a driver state detecting means for detecting an inattentive state of a driver and a dozing state.

[0010] WO 2008 / 044 119 A2 describes a vehicle-mounted warning device comprising an inattention time measuring device that measures the duration of a driver's inattentive state.

[0011] DE 103 50 276 A1 shows a device for fatigue warning in motor vehicles, with a driver sensor system for detecting driver fatigue and with a distance warning system.

[0012] A motor vehicle warning system for an unsafe following distance is known from US 6 388 580 B1.

[0013] DE197 29 613 A1 discloses a driving assistance system for a vehicle, by which a driver is advised to pay attention to a vehicle driving ahead.

[0014] DE 69 213 196 T2 shows a warning device for a vehicle.

[0015] DE 10 2009 012 407 B3 discloses a device for controlling an adaptive restraint system for protecting an occupant of a vehicle.

[0016] A significant disadvantage of existing systems is that fatigue detection and attention assessment cannot always be performed accurately or reliably, especially not in all driving situations. This can result in unnecessary or intrusive warning messages and, in the worst case, either a lack of system response or inappropriate interventions in the driving dynamics. This leads to a loss of acceptance of such systems among drivers and can even cause or trigger dangerous situations.

[0017] The invention is therefore based on the object of developing the known methods and systems and of providing a solution with which the fatigue detection or attention assessment of vehicle drivers can be made better and more reliable.

[0018] This object is achieved by a method having the features of claim 1 and by a driver assistance system having the features of claim 7. Advantageous embodiments and further developments are the subject of subclaims, whereby combinations and further developments of individual features are also conceivable.

[0019] A key concept of the invention is to consider the distance and / or relative speed between the driver's own vehicle and a vehicle ahead when detecting fatigue and / or assessing attention. In this case, the driver's reaction time can be determined based on threshold values ​​or by observing the temporal progression of the change in one or both variables.

[0020] The method according to the invention is used for detecting fatigue and / or assessing attention in a driver of a vehicle, in particular for detecting impending or onset microsleep.

[0021] Within the scope of the method according to the invention, a distance and / or a relative speed to a vehicle driving ahead are taken into account when detecting fatigue and / or assessing attention.

[0022] The method according to the invention can be used both independently and in conjunction with already known methods for driver fatigue detection and / or attention assessment. In particular, an existing driver assistance system that, for example, performs fatigue detection and / or attention assessment using an optical detection system (e.g., an interior camera) can be further developed to incorporate the method according to the invention.

[0023] If the method according to the invention detects that the driver of the vehicle is tired and / or inattentive, a warning can be issued to the driver and other vehicle occupants, for example, and / or safety devices in the vehicle can be triggered or pre-conditioned, such as airbags and seatbelt tensioners. Furthermore, a warning can be issued to other road users, for example, through acoustic or visual signals.

[0024] In an advantageous embodiment of the method according to the invention, when considering the distance to the vehicle in front, a temporal progression of a change in the distance to the vehicle in front is taken into account. In particular, it is possible to evaluate how frequently and / or how significantly the absolute distance to the vehicle in front changes over time. The temporal progression of the change in the distance will exhibit fewer and less pronounced changes for an attentive / alert driver than the temporal progression for a tired / inattentive driver. This allows for fatigue detection and / or attention assessment in a particularly simple and advantageous manner.

[0025] According to the invention, when the distance is taken into account, an undershoot of a target distance to the vehicle in front is taken into account. The target distance can in particular be understood to mean a defined threshold value which the driver is to maintain, e.g. the legally prescribed minimum distance. The target distance can also be a critical distance to the vehicle in front, for example a distance at which a timely reaction by the driver is just possible, e.g. in the event of an emergency braking by the vehicle in front. A key advantage of this embodiment is that if the driver undershoots the target distance and it is concluded that the driver is inattentive or tired, safety-relevant functions can still be triggered in good time, in particular emergency braking of the vehicle.

[0026] In a further preferred embodiment of the method according to the invention, the frequency of undershooting the target distance from the vehicle in front is taken into account. Frequency refers, in particular, to the absolute number of times the target distance is undershot. Experience shows that even an attentive and alert driver can briefly undershoot a critical distance or the target distance from the vehicle in front. By requiring the driver to undershoot the target distance with a certain frequency, false warnings and false triggering of safety functions can be avoided.

[0027] In an advantageous embodiment of the method according to the invention, the frequency of undershooting the target distance to the vehicle ahead within a defined time period is taken into account. By using the time period as an additional criterion, which is in particular a defined time window from which the frequency of undershooting the target distance is recounted, false warnings and false triggering can be advantageously further avoided. The time window can, for example, be a period of 30 seconds, 1 minute, or 5 minutes.

[0028] According to the invention, when taking into account the underrun of the target distance to the vehicle in front, the percentage underrun of the target distance is taken into account, for example, with 0% = no underrun (maintaining the target distance) and 100% = 0 m distance (collision). With this embodiment of the method according to the invention, multi-stage safety strategies can also be advantageously defined. For example, with acoustic warnings, the greater the percentage underrun of the target distance, the more intense the warning can be, e.g., by increasing the volume of a warning tone proportionally to the percentage underrun of the target distance to the vehicle in front.

[0029] In a particular embodiment of the method according to the invention, a change in the relative speed is taken into account during fatigue detection and / or attention assessment, particularly when considering the relative speed to the vehicle in front. Relative speed is understood to mean, in particular, the positive or negative difference between the speed of the driver's own vehicle (the speed of the vehicle in which the method according to the invention is used) and the speed of the vehicle in front, i.e., in particular, the vehicle directly ahead in the same lane.

[0030] In a further particular embodiment of the method according to the invention, the change in the relative speed to the vehicle ahead is taken into account within a defined time range and / or a temporal progression of the change in the relative speed to the vehicle ahead is taken into account, in particular how often and / or to what extent the driver falls below or exceeds a relative speed of 0 km / h within a defined time range. Experience has shown that even an attentive and alert driver will briefly deviate from the relative speed of 0 km / h to the vehicle ahead, for example if the driver of the vehicle ahead unexpectedly changes the speed of his vehicle. The time range or the observation of the relative speed and its change over time can advantageously further prevent false warnings and false activations.The temporal course of the change in relative speed will show fewer and less pronounced changes for an attentive / awake driver than the temporal course for a tired / inattentive driver.

[0031] The driver assistance system according to the invention serves to detect fatigue and / or assess the attentiveness of the driver of a vehicle, in particular to detect impending or onset microsleep. The driver assistance system is preferably arranged in a vehicle and is designed in particular to implement the method according to the invention according to one of the aforementioned embodiments. For this purpose, the driver assistance system preferably comprises means and / or is connected to means for detecting the distance and / or the relative speed between the host vehicle, in which the driver assistance system according to the invention is arranged, and a vehicle traveling ahead in the same lane. The means for detecting the distance and / or the relative speed can be any known system with which one or both of these variables can be determined.Examples of distance measurement devices in vehicles include radar, lidar, and / or camera systems with evaluation devices for distance measurement and / or for determining relative speeds. Telematics devices can also be used to determine these variables, such as vehicle-to-vehicle (car-to-car) or vehicle-to-infrastructure (car-to-X) communication devices.

[0032] Further advantages and optional embodiments of the invention will become apparent from the following embodiment.

[0033] According to one embodiment, the method according to the invention is used in a system, in particular in a driver assistance system which is arranged in a vehicle, which serves to assess the attention or fatigue detection of the driver, ie for example to assess and detect whether the driver is about to fall asleep at the wheel or has already started to fall asleep at the wheel and / or whether the driver is concentrating sufficiently on the traffic situation.

[0034] According to the invention, the distance and / or relative speed to a vehicle ahead is taken into account when detecting fatigue or assessing attention.

[0035] The method according to the invention can also be used in particular in a driver assistance system in which fatigue detection and an assessment of the driver's attention level are carried out based on further criteria. For example, systems are known in which the driver's line of sight and / or eyes are monitored by means of an optical detection device, in particular by means of an interior camera, so that a conclusion can be drawn about the driver's state of drowsiness based, for example, on the basis of information obtained from the pupils, eyelids, eyelid beat, rolling movements of the eyeballs and pupil movements. Furthermore, systems are known in which sensors on the vehicle's steering wheel, for example touch sensors or torque sensors, are used to determine whether the driver has the vehicle under control.In particular, an existing driver assistance system for attention assessment, for example one of the systems mentioned above or one of the systems just mentioned, can be further developed using the method according to the invention.

[0036] The proposed method is based in particular on the knowledge that an attentive (concentrated) and alert driver will generally maintain an essentially constant distance and an essentially constant speed or relative speed from the vehicle in front when following or driving in convoy. An alert and alert driver will, in particular, maintain a relative speed of essentially 0 km / h, unless they intend to overtake the vehicle in front. Furthermore, the method according to the invention is based on the knowledge that an alert and alert driver takes corrective measures (steering and acceleration interventions) very quickly even with slight changes in speed and distance, so that over time only slight fluctuations in distance and speed around a desired and / or target distance and around a relative speed of 0 km / h occur.

[0037] A fatigued and / or inattentive driver, on the other hand, will have difficulty maintaining a constant distance to the vehicle in front and / or a constant relative speed of 0 km / h. Rather, a fatigued / inattentive driver will have to intervene more frequently and more drastically in the steering and acceleration of the vehicle to restore a desired or target distance and / or to adjust the speed of their own vehicle to that of the vehicle in front. In particular, an inattentive / overtired driver will fall below a target or critical distance to the vehicle in front more often and to a greater extent than an alert / attentive driver.

[0038] Within the scope of the method according to the invention, the distance can be determined, for example, by means of a distance radar, by means of a stereo camera for distance determination and / or by means of another device. From the distances at two or more points in time, the relative speed to the vehicle in front can also be continuously determined. The method or the driver assistance system in which the method according to the invention is used can, for this purpose, in particular also be connected to sensor devices already present in the vehicle and used, for example, for other / additional driver assistance systems. Within the scope of the method according to the invention, the information about the distance and relative speed can, for example, also be obtained from devices such as a cruise control or an adaptive cruise control system (e.g. ACC, Adaptive Cruise Control) of the vehicle.In addition, it is possible to determine such information alternatively or additionally via a vehicle-to-vehicle or vehicle-to-infrastructure communication device, for example by vehicles communicating their own speeds and / or positions with each other.

[0039] Taking into account the distance and / or the relative speed to the vehicle in front, the driver's attention or fatigue can now be determined in different ways.

[0040] In a simple design, - if a defined threshold value for the distance is undershot once (e.g. target distance), - in the event of a one-time deviation of the distance from a target distance by a defined threshold value (both positive and negative deviations) and / or - if there is a one-time deviation from the relative speed of 0 km / h by a defined threshold, it is concluded that the driver is inattentive and / or tired.

[0041] Furthermore, the frequency of the respective deviation or undershoot can be observed, especially within a certain period of time. If the frequency exceeds a defined threshold, it can be concluded that the driver is inattentive and / or tired.

[0042] For example, percentage deviations or undershoots of distance and / or relative speed can also serve as threshold values.

[0043] In particular, in the event that safety-relevant measures are triggered as a function of the attention assessment and / or fatigue detection carried out within the framework of the method according to the invention, such as the issuing of warnings, the preconditioning or activation of occupant protection systems and / or interventions in the driving dynamics, then multi-stage intervention strategies can also be defined, for example. In particular, several threshold values ​​can be defined, whereby, for example, when a first threshold value is reached, an acoustic, haptic or visual warning is issued to the driver, when a second threshold value (next higher / critical threshold value) is reached, measures are preconditioned, and when a third threshold value (highest threshold value) is reached, the measures are triggered, in particular a triggering of safety devices and / or interventions in the driving dynamics.

Claims

[1] Method for detecting fatigue and / or assessing the attention of a driver of a vehicle, in particular for detecting an impending or onset of microsleep, where When detecting fatigue and / or assessing attention, a distance and / or a relative speed to a vehicle in front are taken into account, characterized by , that a temporal progression of a change in the distance to the vehicle in front is taken into account, whereby the distance is determined by means of a distance radar, and / or by means of a stereo camera for distance determination, and / or by means of another device, and the information on distance and relative speed is determined alternatively or additionally via a vehicle-to-vehicle or vehicle-to-infrastructure communication device, where Depending on the attention assessment and / or fatigue detection carried out within the procedure, safety-relevant measures are triggered, such as issuing warnings, pre-coordination and / or triggering of occupant protection systems, and / or interventions in driving dynamics, whereby multi-stage intervention strategies are defined and / or several threshold values ​​are defined in such a way that when a first threshold value is reached, an acoustic warning is given to the driver of the vehicle, when a second threshold value is reached, measures are pre-coordinated and when a third threshold value is reached, measures are triggered, such as triggering of safety devices and / or interventions in the driving dynamics, whereby an undershoot of a target distance to the vehicle in front is taken into account and whereby when taking into account the undershoot of the target distance to the vehicle in front, a percentage undershoot of the target distance is taken into account, whereby at 0% there is no undershoot of the target distance and at 100% there is no distance to the vehicle in front. [2] Method according to claim 1, characterized bythat the frequency of the target distance to the vehicle in front being undercut is taken into account. [3] Method according to claim 2, characterized by that the frequency of falling below the target distance to the vehicle in front within a defined time period is taken into account. [4] Method according to one of the preceding claims, characterized by that a change in the relative speed to the vehicle in front is taken into account. [5] Method according to claim 4, characterized by that the change in the relative speed to the vehicle ahead is taken into account within a defined time range. [6] Method according to claim 4 or 5, characterized by that a temporal progression of the change in the relative speed to the vehicle in front is taken into account. [7] Driver assistance system for fatigue detection and / or attention assessment of a driver of a vehicle, in particular for detecting impending or onset microsleep, characterized by that the driver assistance system is designed to implement a method according to one of the preceding claims and comprises means and / or is connected to means for detecting the distance and / or the relative speed between the vehicle and a vehicle traveling ahead.