EP1750236B1 - Method and device for controlling a driver assist system - Google Patents

Abstract

Controlling method involves identifying danger situation on the basis of comparison limit value given by the measuring data, if it identifies a danger situation, a warning signal is generated. A control module is in driver assistance system which determines a characteristic value (A) depending upon input value and a conclusion is made on the activity of the driver. The activity of driver calculates the threshold value (Amin) which depends upon average value whereby a warning signal is suppressed if the characteristic value exceeds the threshold value. An independent claim is also included for the device for motor vehicle for execution of the method.

Description

The present invention relates to a method for controlling a driver assistance system which, on the basis of a comparison of measured data with predetermined limit values, identifies a dangerous situation and, if it has identified such a dangerous situation, can issue a warning signal.

In addition, the present invention relates to a device for carrying out such a method, which comprises a driver assistance system with a signal output device and an additional control module connected to the driver assistance system.

Driver assistance systems and associated control methods and devices for carrying out such methods are known from the prior art. For example, driver assistance systems exist which measure the distance to a preceding vehicle or obstacle and compare this distance with a stored minimum distance. If the stored minimum distance is undershot, a warning signal is issued by the driver assistance system. Also known are so-called "Lane Departure Warning" systems which warn the driver if he accidentally leaves the lane. Such driver assistance systems known from the prior art thus identify a danger situation on the basis of a comparison of certain measured values, such as the distance to the vehicle in front Vehicle, with generally already factory-stored limits.

A disadvantage of these driver assistance systems is that the preset limits do not result in a satisfactory result for each driver and for each driving style. In particular, a warning signal is often output even if the driver deliberately changes lanes, drives up close to the vehicle driving in front of him or otherwise enters a situation identified by the driver assistance system as a dangerous situation. In this case, a warning by the driver assistance system on the part of the driver is not desired, and the issued warning signal may even lead to a dangerous fault reaction of the driver contrary to the original intention. In any case, many drivers find it annoying to hear a warning signal on a regular basis even though they are driving in a concentrated manner, so there is no need for a warning from their point of view. The described inadequacies of conventional driver assistance systems result in many drivers regularly completely deactivating the driver assistance system. As a result, the driver assistance system can of course no longer issue a warning signal even in a real dangerous situation.

From the DE 101 63 967 A1 a driver assistance system is known, which derives from the operation or non-operation of controls an attention condition of the driver. For example, high attention is paid to pedal, gas, brake or gear pedals, while actuation of infotainment devices is ineffective for an inattentive driver. The attentiveness state of the driver thus obtained is used inter alia to estimate a reaction time of the driver and thus serves to intervene of the driver assistance system to cases where this is really necessary.

It is therefore an object of the present invention to provide a method for controlling a driver assistance system of the type mentioned and an associated apparatus for carrying out such a method, which are better able to distinguish critical hazardous situations of non-dangerous risk situations, and possibly only issue a warning signal if this is really necessary.

This object is achieved by a method according to claim 1 and an associated device according to claim 8.

In the method according to the invention, an additional control module determines an activity state of the driver as a function of at least one input value which allows a conclusion to be made by a driver and can suppress the issuing of the warning signal in dependence on this activity state.

The device according to the invention comprises, in addition to the driver assistance system with a signal output device, a control module connected to the driver assistance system, which comprises an electronic unit for determining an activity state of the driver and is in communication with measuring devices provided in the vehicle.

The activity state determined by the method according to the invention provides information about how active or inactive the driver is. Since the activity of the driver is generally an indicator of his or her attention, it can be better judged by an adequate consideration of the corresponding state of activity whether a "real" dangerous situation exists. For example, if the driver is driving straight ahead for a long period of time at a constant speed during a long monotonous highway travel, it is recognized in the method according to the invention that the activity state of the driver corresponds to such a low activity that the driver's attention is likely to diminish , In this case, a warning signal from the driver assistance system is meaningful, and thus the outputting of the warning signal is not suppressed. On the other hand, if the driver is very active, for example frequently changing lanes, flashing, overtaking, braking and accelerates, the additional control module can determine from the input value, which allows conclusions about such actions performed by the driver, that the driver's activity state corresponds to a high activity, so he presumably drives attentive and concentrated. The issuing of the warning signal would be unnecessary in this case with high probability, since the driver obviously consciously goes into a "dangerous situation". The warning signal is suppressed by the inventive method in such a case, so that the driver is not bothered by a superfluous warning signal and thus is not tempted to disable the driver assistance system.

Advantageous developments of the invention are described in the subclaims and the description which follows, as well as in the description of a preferred embodiment given together with the attached figures.

According to the invention, the control module determines a numerical characteristic value for the activity state of the driver on a discrete or continuous scale and suppresses the issuing of the warning signal if this characteristic value is above a predetermined threshold value.

In the simplest case, such a scale may comprise only two values, for example 0 for an inactive state and 1 for an active state. If the characteristic value is greater than or equal to 1, ie if the control module has identified the activity state as "active", the issuing of the warning signal is suppressed. But it is also a finer broken discrete or continuous scale conceivable. The latter is particularly useful when the control module uses a plurality of input values to determine the numerical characteristic. So can different indicators of the driver's activity status are adequately considered. If the characteristic value exceeds the threshold value, it is assumed that the driver is sufficiently active and thus attentive enough not to require a warning signal. The threshold value with which the calculated numerical characteristic value is compared can be preset at the factory or can also be selected as a function of the driving behavior of a driver, as will be explained later.

According to an advantageous embodiment of the invention, the control module determines a numerical characteristic for the activity state on a discrete or continuous scale and suppresses as described above, the output of the warning signal when this characteristic value exceeds a first threshold. In addition, however, at least one further second threshold value is provided, which lies below the first threshold value. If the characteristic value exceeds this second threshold value but is below the first threshold value, the limit values by means of which the driver assistance system identifies a dangerous situation are adjusted. The limit values are adjusted so that the criteria by which the driver assistance system classifies a situation as a dangerous situation become more stringent. For example, in distance warning system, the minimum distance from a vehicle in front, below which a warning signal is issued, can be reduced. It is therefore to some extent an intermediate state in which the driver is indeed active, but may not be sufficiently alert to react quickly in the event of a high risk even without a corresponding warning signal. Consequently, the driver assistance system is not completely deactivated, but only warns of a dangerous situation later. Of course, not only two, but also a larger number of thresholds may be provided, wherein the of the Driver assistance system used limits then depending on the current characteristic value for the activity state gradually adjusted.

According to a further preferred embodiment of the invention, as an alternative or in addition to the procedure described above, different threshold values may be provided for different types of dangerous situations. For example, the threshold for the activity state above which a warning signal is suppressed or limits used by the driver assistance system may be different, depending on whether a warning signal is output because the distance to a preceding vehicle is too low, because a solid centerline is driven over, or because the speed is not adapted to the road conditions. This can take into account the fact that certain types of dangerous situations can also be overlooked by a very active driver or deliberately ignored, while other dangerous situations are generally noticed by an active and attentive driver even without the assistance of the driver assistance system.

As mentioned above, the threshold or thresholds can be set at the factory. In such a method, only a comparatively small amount of computation is needed.

According to a preferred embodiment of the invention, a yaw rate of the vehicle and / or a steering angle as a function of time serve as an input value for the control module. The rate of rotation provides information about how fast the vehicle is turning about a vertical central axis and thus is indirectly related to the driver's steering activity. The steering angle provides direct information about steering activity and thus can be used as the input to the control module instead of the yaw rate. At high rotation rates or at a constantly changing steering angle can be concluded on an increased activity of the driver, while a constant steering angle, especially when the steering wheel is not turned off, close to a low activity and thus also to a possibly reduced attention of the driver.

According to another preferred embodiment of the invention, the control module uses as input value a speed of the vehicle and calculates an acceleration for determining the activity state of the driver from the temporal evolution of the speed. While a constant speed over a long period of time is an indicator of low driver activity, high accelerations, both positive sign and negative sign, indicate high driver activity and thus an attentive driver. Since the speed of the vehicle is available as a measured value in each vehicle, the calculation of the acceleration from the speed gives a variable which is a reliable indicator of the driver's activity without the need for additional measurements.

According to a further advantageous development of the invention, an actuation of a turn signal, a brake and / or an electric built-in appliance by the driver serves as an input value for the control module. It is possible with relatively little effort to determine whether the turn signal and / or the brake are being actuated, and both an operation of the turn signal and an actuation of the brake allow the conclusion that the driver is alert and concentrated. Vice versa Obviously, the driver's attention is not directed exclusively to driving the vehicle when, for example, he tunes to a radio station or operates a navigation system. An operation of an electric built-in device by the driver is thus an indicator of an activity state in which a warning signal rather should not be suppressed.

Of course, the previously enumerated possible input values can be used both individually and together in all conceivable combinations. For example, an acceleration from the vehicle speed can be calculated and additionally monitored whether the driver operates the turn signal. In this case, for example, an activity state parameter calculated by the control module may be proportional to the calculated acceleration, and once again a fixed value is added to the characteristic value during an operation of the turn signal detected within the last few minutes. The use of other additional input values is also conceivable, preferably using information that is available in the vehicle anyway.

According to the invention, the control module determines a time average of a characteristic value for the activity state of the driver and calculates a threshold value as a function of this mean value, wherein a warning signal is suppressed if the characteristic value for the activity state exceeds this threshold value.

In this way, the inventive method can be adapted individually to the behavior of the driver. For a driver who generally has a very sporty driving style, the time average of the Characteristic for the activity state to be higher than for a cautious and leisurely driver. If the state of activity characteristic is close to or above the individual average, however, in both cases one can assume that the driver is so attentive that he does not need a warning signal or only at a very late stage. As a threshold value, it is thus possible, for example, to select a value which lies below the individual mean value of the characteristic value by a certain fraction, so that a warning signal is only suppressed when the driver has at least almost reached its mean activity state. In a less spirited driver, the warning signals of the driver assistance system will thus be suppressed already at a lower characteristic value for the activity state than with a sporty driver.

In this case, it is possible to calculate a time average of the characteristic value for the activity state for a particular driver once over a certain period of time and then to store this value. If a device is used which identifies the driver when starting the vehicle, the threshold assigned to this driver can automatically be called up and used in each case.

However, it is also possible to determine a new average of the characteristic value for the activity state of the driver each time the vehicle is restarted, which is then stored after a certain period of time or even updated during the journey at regular intervals. In this case, the form of the driver and the current traffic conditions can be taken into account.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung und

Fig. 2

ein Ablaufdiagramm, welches das erfindungsgemäße Verfahren veranschaulicht.

In the following, the invention with reference to a preferred embodiment with reference to the two accompanying figures will be described purely by way of example. The figures show:

Fig. 1

a schematic representation of a device according to the invention and

Fig. 2

a flow chart illustrating the inventive method.

The device according to the invention, which is installed in a motor vehicle, is shown schematically in FIG. 1 and comprises a control module 10 and a driver assistance system 20. Various measuring devices 2, 4, 6, 8 belonging to the vehicle are schematically illustrated on the left in FIG and are connected to the control module 10 to transmit signals thereto. From a tachometer 2, a speed v is given to the control module, and a sensor 4 measures the pressure applied to a brake pedal or the pedal position of the brake pedal and outputs a corresponding measurement value to the control module 10. A steering angle sensor 6 measures the angular position of the steering wheel and outputs Finally, a sensor 8 monitors the operation of the turn signal and outputs a corresponding input signal to the control module 10 when the turn signal is actuated. Of course, other input values can be used in addition to the four enumerated input values. For example, instead of the steering angle sensor 6, a sensor can be used which measures the rate of rotation of the vehicle.

In the flowchart shown in FIG. 2, for the sake of simplicity, a method is shown in which the speed v of the vehicle, which is measured in a first step 100, is used as the only input value. Of course, under a Method, as shown in Fig. 2, also other input values are processed.

The driver assistance system 20 illustrated in FIG. 1 is a distance warning system which receives information about a distance d to a vehicle in front from a radar 18. In an electronic unit 22 within the driver assistance system 20, the measured distance d is constantly compared with a stored minimum distance d _min . If d drops below the minimum distance d _min , a warning signal is output by the signal output device 22 in the normal case, which is also part of the driver assistance system 20.

The control module 10 shown in FIG. 1 comprises an electronic unit 12, in which a characteristic value A for an activity state of the driver is calculated. In the flowchart of FIG. 2, the calculation of the characteristic value for the activity state A in step 300 is shown. As can be seen in FIG. 2, the calculation of the characteristic value A in step 300 is preceded by a calculation of an acceleration a from the time evolution of the measured velocity v (step 200 in FIG. 2). This calculation is also performed by the electronic unit 12.

The calculated characteristic value A for the activity state, which in the simplest case shown in FIG. 2 is proportional to the acceleration a of the vehicle calculated in step 200, is supplied by the electronic unit 12 to a comparator module 14, which is also part of the control module 10 is (see Fig. 1).

In the comparator module 14, the calculated characteristic value A for the driver's activity state is compared with a threshold value A _min (see step 400 in FIG.

If the current characteristic value A is greater than the threshold value A _min , the warning signal which the driver assistance system 20 normally outputs is suppressed (compare step 500 in FIG. For this purpose, both the entire driver assistance system can be deactivated, and only the signal output unit 24 can be deactivated. Alternatively, the outputting of the signal can also be suppressed electronically within the driver assistance system 20.

If it is determined in the comparison of the characteristic value A with the threshold value A _min (step 400 in FIG. 2) that the activity A is smaller than the threshold value A _min , the warning signal is not suppressed.

In any case, irrespective of whether the warning signal has been suppressed in a step 500 or not, the method illustrated in FIG. 2 is restarted after the described method steps have been completed. It can either run continuously or restart at preselected intervals.

After the method step 300, in which a characteristic value A for the activity state is determined, it is possible to provide a further method step, not shown in FIG. 2, in which from the characteristic value A calculated in step 300, a time average for this characteristic value A is calculated. From this mean value, an individual threshold value A _min can then be calculated in a further step, for example by adding a time average of the characteristic value A fixed value is deducted. This average value is then passed to the comparator module 14 in the control module 10.

FIG. 2 shows, for the sake of simplicity, a method in which the characteristic value A calculated in step 300 is compared only with a single threshold value A _min . However, it is also possible for a plurality of different threshold values A _min , A _{min 2} , etc. to exist. In this case, the comparator module 14 performs a more complex comparison. If the characteristic value A is above the highest threshold value A _min , the warning signal is still suppressed. However, if the calculated characteristic value A is below the highest threshold value A _min but above a lower threshold value A _min2 , the limit value used by the driver assistance system 20 to identify a dangerous _situation is adjusted accordingly. In the exemplary embodiment illustrated in FIG. 1, the minimum distance d _min would thus be reduced in this case.

LIST OF REFERENCE NUMBERS

2

speedometer

4

Brake pedal sensor

6

Steering angle sensor

8th

Sensor turn signal operation

10

control module

12

electronic unit of the control module 10

14

Comparator module of the control module 10

16

Radar for distance measurement

20

Driver assistance system

22

electronic unit of the driver assistance system 20

24

Signal output device of the driver assistance system 20

A

Characteristic for the activity state

A _min

Threshold for activity state

a

Acceleration of the vehicle

d

Distance to the vehicle in front

v

Speed of the vehicle

Claims (8)

1. Process for controlling a driver-assistance system (20), which may identify a dangerous situation using a comparison of measured data with preset limiting values, and when it has identified such a dangerous situation, may emit a warning signal, wherein an additional control module (10) is provided, which determines a characteristic value (A) for activity of the driver as a function of at least one input value, which permits a conclusion on actions carried out by a driver, determines a temporal average value of this characteristic value (A) and calculates a threshold value (A_min) as a function of this average value, wherein a warning signal is suppressed when the characteristic value (A) for the activity exceeds this threshold value (A_min).
2. Process according to claim 1, characterised in that when the characteristic value (A) for the activity exceeds a first threshold value, the output of the warning signal is suppressed, and when the characteristic value exceeds a second threshold value, but lies below the first threshold value, the limiting values, with reference to which the driver-assistance system (20) identifies a dangerous situation, are adapted.
3. Process according to claim 1 or 2, characterised in that various threshold values (A_min) are provided for different types of dangerous situations.
4. Process according to one of claims 1 to 3, characterised in that the threshold value or values (A_min) is/are fixed at the factory.
5. Process according to one of the preceding claims, characterised in that a rate of rotation of the vehicle and/or a steering angle as a function of the time serve as input values for the control module (10).
6. Process according to one of the preceding claims, characterised in that the control module (10) uses a speed (v) of the vehicle as an input value and to determine the characteristic value (A) for the activity of the driver, calculates an acceleration (a) from the temporal development of the speed (v).
7. Process according to one of the preceding claims, characterised in that actuation of an indicator, a brake and/or a built-in electrical device by the driver serves as an input value for the control module.
8. Device for a motor vehicle for carrying out a process according to one of the preceding claims having a driver-assistance system (20) with a signal-output device (24) and a control module (10) connected to the driver-assistance system (20) and which comprises an electronic unit for determining a characteristic value (A) for activity of the driver and is connected to measuring devices (2, 4, 6, 8) provided in the vehicle.

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