DE102007027000B4 - Lane departure warning and method for warning the driver of a vehicle - Google Patents

Abstract

Lane departure warning for a vehicle, wherein the lane departure warning (1) (a) a lane recognition device (3) for detecting a deviation as a cross-shelf of the vehicle (16) of a lane (17) and (b) a warning device (4) for warning the driver in Depending on the deviation comprises, (c) wherein the lane departure warning comprises an activity device (6) which is adapted to determine from the time course of the setting of at least one operating element driver activity, so that the warning both in dependence on the deviation and in dependence (d) wherein the lane departure warning is arranged to warn the driver when a certain limit value of the deviation is exceeded, (e) wherein the lane departure warning is designed to determine the limit in dependence on the driver's activity, (f) where the difference of the adjustment is calculated to a previous value, (g) where only dif be taken into account, which are above a predefined threshold, and (h) where the difference serves as an index for driver activity.

Description

The invention relates to a lane departure warning system according to the preamble of claim 1. The invention further relates to a method for warning the driver of a vehicle when leaving the traffic lane.

Lane departure warning systems warn the driver of a vehicle against leaving the lane unconsciously, so that he can return his vehicle to the lane by active steering intervention. For example, the vehicle may leave the lane unconsciously because the driver falls asleep or is inattentive for a brief moment. If the driver leaves the lane with his vehicle, the danger arises that the driver loses control of his vehicle or collides with other vehicles. To reduce these risks, lane departure warning systems have been developed.

Known lane keeping assistants detect the position of the vehicle relative to the traffic lane and then issue a warning if a certain distance from a lane marking, for example the lane edge, is undershot. The warning is audible, visual or haptic.

In the known lane departure warning systems, it is problematic to set a limit value for the distance to the lane marking, below which the warning is issued:
If the distance is too large for the limit, then the warning is often in such cases, in which there is no dangerous situation. So there is a high rate of "false alarms". Getting used to the "false alarms" causes the driver to ignore a warning in an actual critical situation and not respond adequately to the warning.

If the distance for the limit value is chosen to be relatively small, a warning is issued very late. In the case of a very late warning, the danger arises that the time for a required reaction is no longer sufficient, so that the vehicle can no longer be steered into the lane in good time. In this case, the lane departure warning system has a low sensitivity (detection of dangerous states).

Another problem arises because the driver's reaction time is slower the more inattentive or tired the driver is. However, the influence of the driver's attention is not taken into account in the static limits.

From the DE 10 2004 047 861 A1 For example, a method for assisting the driver of a vehicle in following a lane is known. It is first determined whether the lane is left. If this is the case, it is detected whether there is driver activity or if the driver is distracted. If this check provides an indication that the driver is inattentive, the lane departure warning will be activated. He can then make a steering intervention. A disadvantage of this driver assistance system is that it reacts comparatively late and thus a warning message may be issued too late.

From the DE 102 53 987 A1 an information system is known in a vehicle that provides information to the driver. This information system detects the condition of the driver, for example, whether he is active or tired. Depending on the condition of the driver, it is decided, for example, whether or not a driver assistance system issues a message in the event of a lane change. The disadvantage of this system is that it only decides whether a warning should be issued at all or not.

From the DE 10 2004 027 085 A1 A lane departure warning system is known which outputs a warning at different escalation levels to the driver when detecting a possibly unwanted lane change. This document does not address the question of when to issue a warning at all.

From the DE 102 56 632 A1 a warning strategy in a lane detection of a motor vehicle is known in which, when a critical driving situation is detected, a warning is issued to the driver whose time, duration and / or type of warning in addition to the traffic situation of the vehicle can also depend on whether the Driver is attentive or inattentive.

The DE 60 2004 002 474 T2 discloses an apparatus and method for alerting a driver when a vehicle is deviating from a predefined driving range in a traffic lane.

The object of the invention is therefore to improve an initially mentioned lane departure warning in such a way that it can issue a warning message particularly quickly at a low rate of false alarms and a sensitivity.

The object is achieved by a lane departure warning system according to claim 1.

The invention is further achieved by a method according to claim 13.

By "driver activity" is meant an evaluation of the driver to what extent this driver is currently involved in vehicle operation.

The lane departure warning according to the invention does not work with a predetermined static limit, but determines a driver activity that has an influence on the limit.

If a high driver activity is determined, this speaks for a high attention of the driver. With a high attention of the driver, it is justifiable to increase the limit accordingly, so that a warning is issued relatively late. This late warning is also welcome: Firstly, the driver is in high driver activity able to react relatively quickly to a warning and return the vehicle in time in the lane. On the other hand, the driver is not bothered with a high rate of false warnings that cause the driver to stop responding to the warnings with due attention.

If the driver is inactive, there is the possibility that this is due to inattention or fatigue of the driver. The lane departure warning according to the invention sets in this case the limit value for the warning to a relatively low value. As a result, the warning occurs relatively early, so that even an inattentive driver has sufficient time to safely steer the vehicle back into the lane.

In doing so, the difference is calculated to a previous value, taking into account only differences that are above a predefined threshold, and where the difference serves as an index for driver activity.

The lane keeping assistant according to the invention thus has the following advantages:
The rate of false alarms is reduced. If the driver is active, he will only be warned if he is very close to the lane marking. If the driver is not active, he is already warned when he is even further away from the lane marking with his vehicle.

The lane departure warning system has a high sensitivity even in cases where the driver is tired or distracted and therefore deviates from the track.

Conveniently, such controls are considered for determining driver activity, which provide substantially continuous information about the driver's current attention. So it should be controls that are deliberately activated as often as possible during a journey. In particular, drive elements (eg accelerator pedal), brake elements (eg brake pedal) or steering elements (eg steering wheel) are considered. But it is also to think about direction indicators or couplings.

The settings are expediently recorded periodically. This ensures, on the one hand, that the settings are recorded regularly and changes can be easily determined. Secondly, the periodic recording of the settings is technically easy to implement.

In modern vehicles, a bus system is used for fast data transmission between control units, in particular a CAN bus (CAN: Controller Area Network). In such vehicles, the values of the settings are conveniently transmitted via the bus system. In this way it is possible to incorporate the lane departure warning system according to the invention without major conversion measures and thus cost in known vehicles.

The activity of the driver can be reliably determined by changing settings. When deliberately changing a setting, the driver's attention is required. A conscious change of a setting is thus capable of expressing an activity of the driver.

Suitably, the activity device is designed to determine for each setting the time that has elapsed since the last change of setting. In this way, a rate of change of the setting used for judging the driver's activity is determined.

It may happen that changes are measurable, but do not go back to a conscious behavior of the driver. Such changes do not contain any useful information for evaluating driver activity. Therefore, it is appropriate to consider a change only if the change exceeds a predefined threshold.

In one embodiment, at least two time intervals are assigned for the duration of each setting, which are assigned to different ratings of the driver activity. This makes it easy to categorize driver activity, such as active and inactive categories or active, quiet and inactive categories. In the first example the driver activity is divided into two areas, in the second example in three. Of course, the classification can be further refined in order to take into account any special circumstances. To think about the type of vehicle: z. Passenger cars or trucks. Conceivable is the adaptation to different traffic situations: z. B. Rides mainly on the highway or country road, city driving. Possibly, the classification can also be made dependent on the characteristics of the driver: z. B. Driver with a lot of experience or novice driver.

In one embodiment it is provided that the warning device is designed to output the beginning and the intensity of the warning as a function of both the deviation and the activity. Thus, in this embodiment, not only the timing of the warning is made dependent on the driver's activity, but also the type of warning. With regard to the intensity of the warning, it is possible, for example, to think about the following intensities: weak warning, strong warning, assistance with intervention, strong warning with assistance or reaching a safe state.

According to the invention, the warning device can be designed to emit the warning acoustically, optically, haptically and / or by intervention in the vehicle control system. An optical display is possible, for example, via a central display or a head-up display.

Suitably, the lane detection device is equipped with infrared sensors, laser sensors and / or video sensors. Such sensors are suitable for detecting the surroundings of the vehicle and, if appropriate, evaluating them in an image processing device. Preferably, different sensors are combined to increase the accuracy and reliability of the evaluation.

Suitably, the lane detection device is designed to determine the deviation by comparing the current position of the vehicle or a future position of the vehicle with a lane marking. It is conceivable z. B., to compare the current center of the vehicle with the center of the roadway or the roadside. With regard to the future position of the vehicle, for example, it is possible to detect the transverse placement.

The invention will be explained in more detail with reference to the embodiment shown in the following figures. Show it:

1 a block diagram of a lane departure warning according to the invention,

2 a block diagram for determining an activity of the driver and

3 a schematic course of a vehicle on a road.

In 1 is schematically a lane departure warning 1 shown.

The Lane Keeping Assist 1 includes sensors 2 , The sensors 2 are used to detect the lane on a road and to detect a deviation of the vehicle from the lane. In the present embodiment, the sensors are video sensors, in particular optical cameras, which image the surroundings of the vehicle. The output signals of the sensors 2 are sent to a track detection device 3 transfer. The track recognition device 3 evaluates the images of the sensors 2 out. For this purpose, the track recognition device 3 equipped with an image processing device. The track recognition device 3 transmits the result of the evaluation to a warning device 4 ,

The Lane Keeping Assist 1 includes sensors 5 , which detects drive settings of a driver-operable input member (eg, accelerator pedal), brake settings of a driver-operable brake member (foot brake), and steering adjustments of a driver-operable steering member (steering wheel). The output signals of the sensors 5 be sent to an activity facility 6 transfer. The transmission takes place periodically at about 10 Hz. The transmission of these output signals takes place in the present embodiment via a CAN bus system of the vehicle.

The activity facility 6 comprises a memory unit and a computer unit, which are formed from the output signals of the sensors 5 to calculate an activity of the driver. The calculated activity is sent to the warning device 4 transfer.

The warning device 4 thus obtains data expressing driver behavior (from the lane detection device 3 ) and data expressing driver activity (from the activity facility 6 ). These data together form a two-dimensional matrix, from which the whether and the like of a warning can be taken.

Tabelle 1 Table 1 below shows such a matrix:

Table 1

The driver activity is divided into three areas: "active", "quiet" and "not active". The driver behavior is also divided into three areas: "safe", "uncertain", "dangerous / critical".

In the matrix, the different warning options are entered in the matrix elements assigned to the driver activity and the driver behavior. For example, the matrix element (active, safe) has the entry "system active". This means that the driver is merely informed that the system is active. This can be displayed, for example, via an optical element, such as an LED. In the case of the matrix element (active, insecure), a weak warning is output, for example in the form of an acoustic signal. In the case of the matrix element (not active, dangerous / critical) it is provided that the lane departure warning system 1 engages the vehicle control and the vehicle leads to a safe state, for example, brings to a standstill on the roadside.

Tabelle 2 Table 2 below shows another matrix:

Table 2

This is a 2 × 3 matrix in which the driver activity is divided into the two areas "active" and "not active". The possible warnings are limited to a soft and a loud Nagelbandratterntern. The driver behavior is divided into three areas: "safe area", "dangerous area", "critical area".

The driver behavior is based on the future position of the vehicle, which is defined by the cross-shelf. If the transverse deviation from the track center does not deviate further than 0.2 m, the driver's behavior is classified as "safe". If the lateral deviation of the track center is greater than 0.2 m but less than 0.3 m, the driver's behavior is classified as "unsafe". If the lateral deviation from the center of the lane exceeds 0.3 m, the driver's behavior is classified as "dangerous / critical".

The warning device 4 gives a warning according to the entries in the matrix. Present is via a microphone 7 An audible tone is emitted to increase the driver's attention.

In 2 is the activity facility 6 shown in more detail.

The activity facility 6 includes reception facilities 9a , b, c, which read at a frequency of about 10 Hz data from the CAN bus system of the vehicle.

The receiving device 9a receives the setting of the accelerator pedal. The setting corresponds to the extent to which the driver presses the accelerator pedal. The setting is a value from the interval 0% to 100%. 100% corresponds to the fully depressed accelerator pedal.

The receiving device 9b receives the brake pressure of the foot brake. The brake pressure is a value from the interval 0 bar to 250 bar.

The receiving device 9c receives the steering wheel angle. The steering wheel angle is from the interval -1,400 ° to + 1,400 °.

For each of these three quantities, the difference to the previously received value is calculated. The result is a sequence of value differences or changes, which are also obtained with a frequency of 10 Hz. To avoid random, non-meaningful differences, only changes greater than a predefined threshold are considered. In the present example the threshold values are given as follows: a) Accelerator pedal: 1% referred to the interval 0% to 100%; b) Brake pedal: 1.5 bar referred to the interval 0 bar to 250 bar; c) Steering wheel: 0.5 ° relative to the interval -1.400 ° to + 1.400 °.

For each signal, the difference serves as an index of the driver's activity. If at least one of the signals has changed, an overall activity is assumed at that time. This can be done, for example, by assigning the value "1" (active). If one of the signals has changed during a period, the total activity is set to the value "0" (not active). The total activity is through a module 11 provided.

Is the activity in the module 11 If the value is "0", the duration of the inactivity is summed up. This is done in a module 12 ,

A suitable inactivity threshold is used to calculate an index that represents a measure of driver activity.

The activity is in a module 13 calculated. In the calculation of the driver's activity is also advantageous, the speed v of the vehicle 15 considered.

The activity is finally output in the form of a value "0" (not active), "0.5" (quiet) and "1" (active) and to the warning device 4 transfer.

The determination of the activity taking into account the speed v of the vehicle 15 is explained in more detail below using an example:
The duration of the inactivity is set to zero as soon as a driver's activity is measured, for example because the driver has applied the brake.

If no adjustment is made, the duration of inactivity is measured.

This duration is classified for different speeds.

For speeds below 60 km / h, two thresholds are set as follows: 3 seconds and 8 seconds. These thresholds lead to the three intervals with the associated activities: under 3 seconds ("1" or "active"); between 3 and 8 seconds ("0.5" or "quiet"); over 8 seconds ("0" or "inactive").

For speeds between 60 km / h and 110 km / h, two thresholds are set as follows: 4 seconds and 9 seconds. These thresholds lead to the three intervals with the associated activities: under 4 seconds ("1" or "active"); between 4 and 9 seconds ("0.5" or "quiet"); over 9 seconds ("0" or "inactive").

For speeds in excess of 110 km / h, two thresholds are set as follows: 6 seconds and 12 seconds. These thresholds lead to the three intervals with the associated activities: under 6 seconds ("1" or "active"); between 6 and 12 seconds ("0.5" or "quiet"); over 12 seconds ("0" or "inactive").

In 3 is schematically a part of a roadway 15 shown. On the roadway 15 a vehicle is moving 16 at a speed v along the roadway 15 ,

On the roadway 15 is a lane 17 shown in dashed lines. The lane 17 in this case is the center line of the roadway 15 , The vehicle 16 moves with its center (not shown) on the lane 17 ,

By suitable sensors (not shown), the future vehicle position is extrapolated based on the current speed v. The distance d of the future vehicle position 18 from the lane 17 is the cross-shelf of the vehicle 16 that as deviation from the lane 17 is used.

LIST OF REFERENCE NUMBERS

1

Lane Departure

2

sensors

3

Lane detection device

4

warning device

5

sensors

6

activity unit

7

speaker

8th

vehicle control

9a, b, c

receiving devices

10

CAN bus

11

module

12

module

13

module

14

speed

15

roadway

16

vehicle

17

lane

18

Future vehicle position

Claims (13)

Lane Keeping Assist for a vehicle, with the Lane Keeping Assist ( 1 ) (a) a track recognition device ( 3 ) for detecting a deviation as a transverse deposit of the vehicle ( 16 ) from a lane ( 17 ) and (b) a warning device ( 4 ) for warning the driver as a function of the deviation, (c) wherein the lane departure warning system comprises an activity device ( 6 DB = EPODOC & ... PN = EP0284801), which is designed to determine a driver 's activity from the time profile of the setting of at least one control element, so that the warning takes place both as a function of the deviation and as a function of the driver' s activity (d) wherein the lane departure warning system is designed to control the Warning the driver when a certain limit value of the deviation is exceeded, (e) wherein the lane departure warning is adapted to determine the limit value in dependence on the driver's activity, (f) wherein the difference of the setting is calculated to a previous value, ( g) taking into account only differences greater than a predefined threshold, and (h) where the difference serves as an index of driver activity. Lane departure warning according to claim 1, characterized in that the at least one operating element is a drive element, in particular an accelerator pedal. Lane departure warning according to claim 1 or 2, characterized in that the at least one operating element is a brake element, in particular a brake pedal. Lane departure warning according to one of the preceding claims, characterized in that the at least one operating element is a steering element, in particular a steering wheel. Lane departure warning according to one of the preceding claims, characterized in that the activity device ( 6 ) is designed to detect the settings periodically. Lane departure warning according to one of the preceding claims, characterized in that the activity device ( 6 ) is configured, the settings from a bus system ( 10 ) read out. Lane departure warning according to one of the preceding claims, characterized in that the activity device ( 6 ) is designed for each Lane departure warning according to claim 7, characterized in that for the duration of each setting at least two time intervals are set, which are assigned to different ratings of the driver activity. Lane departure warning according to one of the preceding claims, characterized in that the warning device ( 4 ) is adapted to give the beginning and the intensity of the warning depending on both the deviation and the driver's activity. Lane departure warning system according to claim 9, characterized in that the warning device ( 4 ) is formed to deliver the warning acoustically, visually, haptically and / or by engaging in the vehicle control. Lane departure warning system according to one of the preceding claims, characterized in that the lane recognition device ( 3 ) Comprises infrared sensors, laser sensors and / or video sensors. Lane departure warning system according to one of the preceding claims, characterized in that the lane recognition device ( 3 ) is formed, the deviation by comparing the current position of the vehicle ( 16 ) or a future position of the vehicle ( 16 ) with a lane marking. Method for warning the driver of a vehicle ( 16 ) when leaving the lane with the steps: - detecting a deviation of the vehicle ( 16 ) from the lane ( 17 ), - determining a driver activity, - determining a limit depending on the driver 's activity and - warning the driver if the deviation is below the limit, - calculating the difference of the attitude to a previous value, - taking into account only differences above a predefined threshold, and - where the difference serves as an index to driver activity.

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