EP0119486A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System and method for detecting driver drowsiness
Assignee: Nissan Motor Co Ltd
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Filing: 1984-02-17
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Granted: —
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Expires: 2004-02-17
Abstract
Abstract A drowsiness alarm system for a vehicle detects and signals that the vehicle driver is drowsy on the basis of the duration during which no steering adjustments are made and the magnitude and speed of abrupt steering adjustments immediately following the non-steering period. Parameters compared to the magnitude and speed of the abrupt steering adjustments in order to recognize steering behavior reflecting drowsiness are adjusted in accordance with the duration of the non-steering period.
Inventors
- 👤 Yasutoshi Seko
- 👤 Haruhiko Iizuka
- 👤 Takayuki Yanagishima
- 👤 Hideo Obara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 19:45
CPC Classifications
G; G08; G08B; G08B21/00; G08B21/02; G08B21/06; A; A61; A61B; A61B5/00; A61B5/16; A61B5/18; B; B60; B60W; B60W2540/00; B60W2540/18
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
204 words
A method for detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular (1;14',18,19-1,19-2) steering wheel and signalling the direction and magnitude of change in the position of the steering wheel; (b) measuring a first duration of period of time (t o ) during which no noticeable changes in the position of the steering wheel are made; (c) determining whether said first duration of period of time(to)measured in said step (b) is longer than any given period of time; (A i ) (d) determining whether noticeable changes in the position of the steering wheel immediately following no noticeable changes in the position of the steering wheel for said first duration determined in said step (c) satisfy any one of predetermined conditions; (e) selecting one of said predetermined conditions in accordance with said first duration (t o ) determined in said step (c); and (f) activating an alarm device(7) indicating driver drowsiness when said first duration is determined to be longer than any given period of time in said step (c) and said noticeable changes in the position of the steering wheel determined in said step (d) satisfy said one of predetermined conditions in said step (e).
Claim 2
Independent Claim
204 words
A method for detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular (1;14',18,19-1,19-2) steering wheel and signalling the direction and magnitude of change in the position of the steering wheel; (b) measuring a first duration of period of time (t o ) during which no noticeable changes in the position of the steering wheel are made; (c) determining whether said first duration of period of time(to)measured in said step (b) is longer than any given period of time; (A i ) (d) determining whether noticeable changes in the position of the steering wheel immediately following no noticeable changes in the position of the steering wheel for said first duration determined in said step (c) satisfy any one of predetermined conditions; (e) selecting one of said predetermined conditions in accordance with said first duration (t o ) determined in said step (c); and (f) activating an alarm device(7) indicating driver drowsiness when said first duration is determined to be longer than any given period of time in said step (c) and said noticeable changes in the position of the steering wheel determined in said step (d) satisfy said one of predetermined conditions in said step (e).
Claim 3
Dependent Claim
32 words
The method of claim 1, wherein said predetermined conditions include a second duration during which the position of the steering wheel changed consistently in one direction which exceeds a first reference value.
Claim 4
Dependent Claim
37 words
The method of claim 2, wherein said predetermined conditions further includes the position of the steering wheel which is changed consistently in one direction at a rate greater than a second reference value during said second duration.
Claim 5
Independent Claim
178 words
A method of detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular (1,14',18,19,19-1,19-2) steering wheel and signalling the direction, magnitude, and rate of change in the position of the steering wheel; (b) measuring a first duration of periods of time during which no noticeable changes in the position of the steering wheel are made; (c) measuring a second duration of periods of ( t 1 (N)) time during which the position of the steering wheel is changed consistently in one direction which exceeds a first (A i ) reference value at a rate greater than a second reference value; (d) activating an alarm device(7) indicating driver drowsiness when no noticeable steering changes in the position of the steering wheel are made and said second (t duration (t 1 (N)) of the period immediately following said no-steering-change period exceeds said first reference value; and (e) adjusting at least one of said first and second reference values in accordance with said measured first duration of said no-steering-change period (t 0 ).
Claim 6
Independent Claim
178 words
A method of detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular (1,14',18,19,19-1,19-2) steering wheel and signalling the direction, magnitude, and rate of change in the position of the steering wheel; (b) measuring a first duration of periods of time during which no noticeable changes in the position of the steering wheel are made; (c) measuring a second duration of periods of ( t 1 (N)) time during which the position of the steering wheel is changed consistently in one direction which exceeds a first (A i ) reference value at a rate greater than a second reference value; (d) activating an alarm device(7) indicating driver drowsiness when no noticeable steering changes in the position of the steering wheel are made and said second (t duration (t 1 (N)) of the period immediately following said no-steering-change period exceeds said first reference value; and (e) adjusting at least one of said first and second reference values in accordance with said measured first duration of said no-steering-change period (t 0 ).
Claim 7
Dependent Claim
66 words
The method of claim 4, wherein said alarm device is activated only when, in addition to the conditions set forth in step (d), a third duration of an additional period satisfying the conditions of step (c) in the direction of change opposite that of said second duration period satisfying the conditions of step (c) and immediately following said second duration period exceeds a third reference value.
Claim 8
Dependent Claim
52 words
The method of claim 5, wherein in measuring said second duration of the period satisfying the conditions of step (c), a fourth reference value is used instead of said second reference value, and said third and fourth reference values are adjusted in accordance with said measured first duration of said no-steering-change period.
Claim 9
Dependent Claim
88 words
The method of claim 4, further comprising the steps of: (f) monitoring an additional vehicle operation parameter and inhibitting execution of any other steps until the vehicle operation parameter satisfies a predetermined condition; (g) inhibitting activation of the alarm or device during a predetermined time period after the vehicle operation parameter first satisfies the predetermined condition; and (h) adjusting a minimum value determining no noticeable changes in the position of the steering wheel in accordance with the duration of the longest no-steering-change period during said predetermined time period.
Claim 10
Dependent Claim
28 words
The method of claim 7, wherein said minimum value is assigned a value fractionally larger than the duration of the longest no-steering-change period during said predetermined time period.
Claim 11
Independent Claim
359 words
A system for detecting driver drowsiness in an automotive vehicle, comprising: a) a first sensor means for detecting the direction and magnitude of rotational movement of a vehicular steering wheel and outputting a steering pulse signal whenever said steering wheel is rotated through a predetermined angle, said steering pulse signal indicating the rotational direction of said steering wheel; b) a first determination means responsive to said output signals from said first sensor means for 'determining whether an episode of non-steering continues for at least a set minimum interval of time on the basis of the interval of time between two consecutive steering pulse signals derived from said first sensor means; c) a second determination means for determining whether a first abrupt unidirectional steering adjustment exceeding a first predetermined angle of steering change and a first predetermined angular speed of steering change occurs, after determination by said first determination means that a non-steering episode has continued for at least said minimum interval of time, on the basis of the intervals of time between consecutive steering pulse signals indicating rotation of steering wheel in a single direction and the number of such steering pulse signals within a first predetermined interval of time, at least one value of said first predetermined angle of steering change and angular speed of steering change being adjusted according to the duration of said non-steering episode determined by said first determination means; d) a third determination means for determining whether a second unidirectional abrupt steering adjustment exceeding a second predetermined angle of steering change and a second predetermined angular speed of steering change in the direction of rotation opposite said first unidirectional abrupt steering adjustment, after said first unidirectional abrupt steering adjustment determined by said first determination means, on the basis of the intervals of time between consecutive steering pulse signals indicating the same direction rotation of the steering wheel and the number of such steering pulses within a second predetermined interval of time; and e) an alarm means responsive to the result of said third determination means for producing an alarm when said third determination means determines that said second unidirectional abrupt steering adjustment has occurred.
Claim 12
Independent Claim
359 words
A system for detecting driver drowsiness in an automotive vehicle, comprising: a) a first sensor means for detecting the direction and magnitude of rotational movement of a vehicular steering wheel and outputting a steering pulse signal whenever said steering wheel is rotated through a predetermined angle, said steering pulse signal indicating the rotational direction of said steering wheel; b) a first determination means responsive to said output signals from said first sensor means for 'determining whether an episode of non-steering continues for at least a set minimum interval of time on the basis of the interval of time between two consecutive steering pulse signals derived from said first sensor means; c) a second determination means for determining whether a first abrupt unidirectional steering adjustment exceeding a first predetermined angle of steering change and a first predetermined angular speed of steering change occurs, after determination by said first determination means that a non-steering episode has continued for at least said minimum interval of time, on the basis of the intervals of time between consecutive steering pulse signals indicating rotation of steering wheel in a single direction and the number of such steering pulse signals within a first predetermined interval of time, at least one value of said first predetermined angle of steering change and angular speed of steering change being adjusted according to the duration of said non-steering episode determined by said first determination means; d) a third determination means for determining whether a second unidirectional abrupt steering adjustment exceeding a second predetermined angle of steering change and a second predetermined angular speed of steering change in the direction of rotation opposite said first unidirectional abrupt steering adjustment, after said first unidirectional abrupt steering adjustment determined by said first determination means, on the basis of the intervals of time between consecutive steering pulse signals indicating the same direction rotation of the steering wheel and the number of such steering pulses within a second predetermined interval of time; and e) an alarm means responsive to the result of said third determination means for producing an alarm when said third determination means determines that said second unidirectional abrupt steering adjustment has occurred.
Claim 13
Dependent Claim
34 words
The system of claim 9, wherein at least one of said second predetermined angle of steering change and second angular speed of steering change is adjusted according to the duration of said non-steering episode.
Claim 14
Dependent Claim
55 words
The system of claim 9, which further comprises means for clocking a predetermined time in response to the output signal from said second sensor means and changing said minimum interval of time set in said first determination means to a value greater than the duration of the longest non-steering episode during the clocked predetermined time.
Claim 15
Dependent Claim
158 words
The sytem of claim 9, wherein said first sensor means comprises: a) a disk linked with the steering wheel so as to rotate with the steering wheel and having a plurality of (14) slits arranged radially symmetrically thereabout, each slit having a width fractionally smaller than said predetermined angle of steering and the spacing between each pair of slits being fractionally greater than said predetermined angle of steering; (19-1,19-2) b) a pair of photo interrupters located near said disk (18) for detecting rotation of said disk and outputting two square-pulse signals having a phase difference corresponding to a half of said predetermined angle of steering; and c) a discriminator means, responsive to the (19-1, 19-2) two output signals from said pair of photo interrupters, for discriminating whether the steering wheel is rotating clockwise or counterclockwise depending on which of the two output signals is leading in phase and outputting said a steering pulse indicative of the discriminated result.
Claim 16
Independent Claim
46 words
The system of any one of claims 6, 7, 8, and 9, which further comprises a second sensor means for detecting a condition prerequisite to starting detection of driver drowsiness and outputting a signal to said first determination means indicating that the prerequisite condition is satisfied.
Claim 17
Dependent Claim
34 words
The system of claim 10, wherein said second (3) sensor means comprises a vehicle speed sensor which outputs said signal to said first determination means indicating that the vehicle speed exceeds a predetermined value.
Claim 18
Independent Claim
195 words
A method for detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular steering wheel and signalling the direction and magnitude of change in the position of the steering wheel; (b) measuring a first duration of period of time during which no noticeable changes in the position of the steering wheel are made; (c) determining whether said first duration of period of time measured in said step (b) is longer than any given period of time; (d) determining whether noticeable changes in the position of the steering wheel immediately following no noticeable changes in the position of the steering wheel for said first duration determined in said step (c) satisfy any one of predetermined conditions; (e) varying one of said predetermined conditions in accordance with said first duration determined in said step (c); and (f) activating an alarm device indicating driver drowsiness when said first duration is determined to be longer than any given period of time in said step (c) and said noticeable changes in the position of the steering wheel determined in said step (d) satisfy said one of predetermined conditions in said step (e).
Claim 19
Independent Claim
195 words
A method for detecting driver drowsiness in an automotive vehicle, comprising the steps of: (a) monitoring the position of a vehicular steering wheel and signalling the direction and magnitude of change in the position of the steering wheel; (b) measuring a first duration of period of time during which no noticeable changes in the position of the steering wheel are made; (c) determining whether said first duration of period of time measured in said step (b) is longer than any given period of time; (d) determining whether noticeable changes in the position of the steering wheel immediately following no noticeable changes in the position of the steering wheel for said first duration determined in said step (c) satisfy any one of predetermined conditions; (e) varying one of said predetermined conditions in accordance with said first duration determined in said step (c); and (f) activating an alarm device indicating driver drowsiness when said first duration is determined to be longer than any given period of time in said step (c) and said noticeable changes in the position of the steering wheel determined in said step (d) satisfy said one of predetermined conditions in said step (e).
References Cited (Backward Citations)
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