U.S. patent application number 10/384862 was filed with the patent office on 2004-02-26 for method and device for warning a driver.
Invention is credited to Maass, Alexander.
Application Number | 20040036613 10/384862 |
Document ID | / |
Family ID | 27762776 |
Filed Date | 2004-02-26 |
United States Patent
Application |
20040036613 |
Kind Code |
A1 |
Maass, Alexander |
February 26, 2004 |
Method and device for warning a driver
Abstract
A method and a device for warning a driver, the magnitude of the
generated warning signal being a function of the probability of the
driver inattentiveness.
Inventors: |
Maass, Alexander; (Leonberg,
DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
27762776 |
Appl. No.: |
10/384862 |
Filed: |
March 10, 2003 |
Current U.S.
Class: |
340/575 ;
340/425.5 |
Current CPC
Class: |
B60W 2540/10 20130101;
B60K 28/066 20130101; B60W 2050/0025 20130101; B60W 2540/12
20130101; B60W 2540/18 20130101; B60W 2540/22 20130101; B60W
2540/221 20200201 |
Class at
Publication: |
340/575 ;
340/425.5 |
International
Class: |
G08B 023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 8, 2002 |
DE |
10210130.2 |
Claims
What is claimed is:
1. A method for warning a driver, comprising: implementing a
warning by at least one of an acoustic, an optical and a haptic
indicator; and generating a warning signal, a magnitude of the
warning signal being dependent upon a degree of driver
inattentiveness.
2. The method according to claim 1, further comprising deriving a
variable, which represents a measure of a driver's inattentiveness,
from at least one operating variable.
3. The method according to claim 1, further comprising modifying,
in an acoustical warning, at least one of a volume and a pitch.
4. The method according to claim 1, further comprising modifying,
in an optical warning, at least one of an intensity, a color and a
size of the optical warning.
5. The method according to claim 1, wherein the warning signal is
generated as a function of at least one of an instantaneous and a
future estimated distance of a vehicle to a demarcation of a
traffic lane of the vehicle.
6. The method according to claim 2, wherein the at least one
operating variable includes at least one of a steering angle, an
accelerator position, a brake-pedal position, a sitting posture and
a posture of a driver.
7. The method according to claim 1, further comprising determining
a plurality of operating variables from which factors representing
a measure of a driver's inattentiveness are generated, which are
linked to form a variable.
8. The method according to claim 1, further comprising determining
a plurality of operating variables from which factors are formed
which, weighted differently, are linked to form a variable
representing an intensity of the warning.
9. The method according to claim 8, wherein the factors are a
function of operating variables.
10. A device for warning a driver comprising: a control unit for
receiving at least one operating variable and outputting at least
one warning signal, the control unit including means for generating
the warning signal, the control unit further including means for
specifying a magnitude of the warning signal as a function of a
degree of a driver's inattentiveness.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to a method and a device
for warning a driver, especially for warning a driver in the event
of driving errors or imminent potential dangers due to
inattentiveness or tiredness.
BACKGROUND INFORMATION
[0002] From the related art, various systems are known which warn a
driver of a motor vehicle when he is inattentive, especially in
those cases where, due to the driver being tired, briefly nodding
off or being distracted (in the following summarized as
inattentiveness), the vehicle leaves, or is in imminent danger of
leaving, the traffic lane. One example of such a system is shown in
German Patent Application No. DE 195 07 956 where sensor elements
determine the distance of the vehicle from a lane marking and the
time for reaching the markings is estimated as a function of the
distance and by taking additional variables into account. The
driver is alerted when he is in danger of straying from the traffic
lane. Problematic in such system is the difficulty of precisely
ascertaining the attention state of the driver. While the change in
the distance of a vehicle to a lane marking does supply indications
of the driver's inattentiveness, it is difficult to reliably
distinguish between a "concentrating driver" and an "inattentive
driver". A large gray area exists in which neither inattention nor
attentiveness of the driver may be assumed. As a consequence, the
following problems result with respect to alerting the driver. If
the driver is warned too early, he will encounter numerous false
alarms, which are felt to be disruptive. If the driver is warned
only when inattentiveness must be assumed with the highest degree
of certainty, the danger exists that not all cases are covered in
which the driver is inattentive.
SUMMARY OF THE INVENTION
[0003] A particular advantage of tying the intensity of a warning
to at least one operating variable from which a probability of
driver inattentiveness may be derived, is that, the higher the
likelihood of driver inattentiveness, the more clearly the driver
is alerted to the warning. Such a warning is rarely perceived as
intrusive by an alert driver, yet sufficiently warns an inattentive
driver.
[0004] Moreover, it is especially advantageous that a concentrating
driver perceives lower, softer warnings than a driver lacking
concentration. Thus, an optimal compromise between the clarity and
the effectiveness of the warning is obtained.
[0005] The adaptation of the warning output is advantageously
specified either as stepless or stepped dependent on the determined
probability of inattentiveness.
[0006] Particularly advantageous is the implementation both in
connection with acoustic warnings in which, in particular, the
volume and/or the pitch are/is modified, and also optical displays
in which the light intensity and/or the color and/or the size of
the warning is/are altered.
[0007] The use in haptic warnings, in which the intensity of
vibrations is changed, for instance, is also advantageous.
[0008] The magnitude (intensity) specifying the warning output is
advantageously determined as a function of different criteria for
ascertaining the attentiveness of the driver, for instance, as a
function of a distance variable of the vehicle to a traffic lane
reference variable (such as the center of the traffic lane, the
edge marking of a traffic lane, etc.), dependent on an estimated
attentiveness based on steering behavior and/or the change in the
position of the accelerator pedal and/or the brake pedal, and/or
dependent on the detected sitting position or posture. In this
manner, essential criteria for determining the attentiveness of the
driver are taken into account and linked to each other to generate
the warning output.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows an overall view of a control device in which
steps are taken for attentiveness detection and for generating the
warning output.
[0010] FIG. 2 shows a flow chart for generating the warning output
in a preferred exemplary embodiment.
DETAILED DESCRIPTION
[0011] FIG. 1 shows a control device 10, which includes an input
circuit 12, a microcomputer 14 and an output circuit 16. These
elements are interconnected via a bus system 18. Input circuit 12
is supplied with input lines which connect control unit 12 to
sensors for detecting operating variables, for instance, of the
vehicle. For example, an input line 20 leads from a sensor 22 for
detecting the accelerator pedal position to input circuit 12. From
a steering-angle sensor 24, a line 26 leads to input circuit 12,
while a line 30 leads from a distance sensor 28, for instance, a
camera, to input circuit 12. From additional measuring devices 32
through 36 (such as a passenger-compartment camera), input lines 38
through 42 lead to control unit 10. Alternatively, it is possible
to receive a plurality of input signals via a bus-transmission (for
instance, a CAN bus), using fewer input lines. Via at least one
output line 44, which originates from output circuit 16, control
unit 10 activates at least one warning device 46, such as a
loudspeaker and/or an optical and/or a haptic warning indicator.
Based on the supplied measuring signals, such as the
accelerator-position signal, brake-pedal position signal,
steering-angle signal, the distance signal to an edge marking of
the traffic lane or the estimated future distance curve and/or
additional signals, such as a signal regarding the posture by a
passenger-compartment camera, at least one variable representing a
measure of the attentiveness or inattentiveness of the driver, and
one variable for the necessity of warning the driver are determined
and evaluated by the programs implemented in microcomputer 14.
[0012] These variables are then combined into a resulting variable.
In one embodiment, the individual variables are linked either
unchanged, for instance, or using variably defined weighting
factors as a function of the operating situation, to form the
resulting variable on whose basis the warning is implemented. For
instance, if the warning is an acoustical warning, the volume
and/or the pitch of the warning are/is specified as a function of
the resulting variable. In a resulting variable which indicates
that an inattentiveness of the driver is highly probable, a high
volume or a high pitch is chosen. In a variable indicating only an
average or low likelihood of driver inattentiveness, a
comparatively softer volume or lower pitch is chosen. If an optical
display is involved, the light intensity and/or color and/or size
are specified as a function of the resulting variable. For
instance, if the color changes from green, for a low probability of
inattention, to red for a high probability, the changes occur
correspondingly, from small to large and/or from low light
intensity to high.
[0013] A preferred exemplary embodiment for realizing such a
program is shown in FIG. 2 with the aid of a flow chart.
[0014] The program sketched in FIG. 2 is run through at specified
time intervals. In first step 100, the distance Abs of the vehicle
from an edge marking of the traffic lane, such as the center
marking or an edge marking, is read in, or the future distance of
the vehicle from an edge marking of the traffic lane, such as the
center marking or an edge marking, is estimated. An example of
determining such a distance is known from the related art mentioned
in the introduction. In the preferred exemplary embodiment, future
distance values are extrapolated from the instantaneous and the
past distance values, the necessity of a driver warning being
assumed in the event of the vehicle approaching the edge marking
with a corresponding reduction in the estimated distance, or in the
event of an imminent crossing of the marking. In the following step
102, the estimated future distance is weighted by a weighting
factor W1. In the next step 104, an attentiveness factor ALW, which
is derived from the steering angle, is read in. To form this
factor, successively occurring steering angles are read in and the
changes analyzed. For example, the factor is determined from the
gradient and/or the frequency of the angle changes and/or the
intervals of successively occurring steering-angle changes as
dictated by characteristic curves, characteristics maps and tables.
It is essential here that the factor increase inversely as the
steering movements slow down or get less. This is an indication of
driver inattentiveness.
[0015] The attentiveness factor ALW is weighted with a second
weighting factor W2 in step 106. Then, in step 108, an
attentiveness factor derived from the accelerator position is read
in. Analogously to the steering angle, this factor is determined,
for instance, from the gradient and/or the frequency of the angle
changes and/or the intervals of successively occurring
accelerator-position changes according to characteristic curves,
characteristic maps, tables, the factor increasing as the changes
in the accelerator position decrease. The latter indicates
inattentiveness. In the following step 110, this factor is weighted
with the weighting factor W3. Additional variables estimating the
attentiveness of the driver may subsequently be incorporated
according to the same principle. Then, in step 112, the intensity
of the warning Iwarn is derived from the weighted variables. For
this purpose, the weighted attentiveness factors are deducted from
the basic value determined from the estimated instantaneous or
future distance to the traffic lane. A warning is then output whose
intensity is a function of the resulting variable Iwarn. This means
that, the greater this resulting variable, the louder the
acoustical, or the more distinct the optical warning display. The
program is then ended and run through again at the next time.
[0016] In another variant, the basic value may be derived in some
other fashion. For instance, the variable may be generated as a
function of falling below a predefined value that is dependent on
the vehicle speed.
[0017] In a preferred exemplary embodiment the weighting factors W1
through W3 are a function of operating variables. For instance, at
high speeds the accelerator factor is rated higher than the
steering-angle factor, whereas the distance value is weighted more
heavily. At low speeds, it may be useful to assign a higher
importance to the steering-angle factor than to the accelerator
factor.
[0018] In addition, or instead of the steering-angle dependency
and/or the accelerator-position dependency in the generation of the
inattentiveness factors, other criteria may be utilized, such as a
change in posture, especially of the head, an inattentiveness
factor being increased when a turning of the head is detected or a
forward pitching of the body. The body posture is being detected by
a passenger-compartment camera, for example.
[0019] When acoustic displays are used, the volume change occurs as
a function of the detected warning-intensity variable, in a
stepless fashion or in several steps. In optical displays,
depending on the design, the size of the display, the color of the
display and/or the intensity of the display is/are changed as a
function of the warning intensity.
[0020] The preferred application of the described procedure is in
combination with a so-called lane-stray warner. However, the above
measures are also advantageously used in other applications, namely
wherever a warning signal is formed to warn a driver of a hazard,
such as in a warning due to an insufficient distance, etc., the
attentiveness of the driver playing an important role in the
effectiveness of the warning.
* * * * *