Apparatus and method for maintaining operator alertness
First Claim
1. An apparatus for intermittently detecting operator alertness and altering stimuli in response to the detected degree of operator alertness, comprising:
- means for initiating successive intermittent first stimuli detectable by the operator;
response means actuated by the operator upon detection of each such first stimulus; and
, detection means responsive to the initiation of each stimulus and the actuation of said response means for selectively modifying subsequent stimuli in inverse proportion to the operator alertness indicated by the detected actuation of the response means by the operator.
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Abstract
Successive stimuli are initiated intermittently at selectively variable time intervals inversely related to the time taken by the operator in responding to the previous stimulus. The time required by the operator to detect and respond to each stimulus automatically varies the timing for initiating the next stimulus. In the preferred form, each stimulus is produced with a gradually increasing intensity, such as by amplitude modulating the volume of an audio tone, until the operator actuates a response switch to terminate the stimulus; and a much more severe stimulus, such as from an alarm bell, is given when no response is made within a given interval after a stimulus is initiated.
51 Citations
15 Claims
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1. An apparatus for intermittently detecting operator alertness and altering stimuli in response to the detected degree of operator alertness, comprising:
- means for initiating successive intermittent first stimuli detectable by the operator;
response means actuated by the operator upon detection of each such first stimulus; and
, detection means responsive to the initiation of each stimulus and the actuation of said response means for selectively modifying subsequent stimuli in inverse proportion to the operator alertness indicated by the detected actuation of the response means by the operator.
- means for initiating successive intermittent first stimuli detectable by the operator;
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2. The apparatus of claim 1 wherein:
- said detection means varies the time period before initiation of stimulus in inverse proportion to the time interval between initiation of the preceding stimulus and actuation of the response means.
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3. An apparatus for intermittently detecting operator alertness and for altering operator stimuli in response to the detected degree of alertness, comprising:
- means for intermittently initiating successive first stimuli, each of which becomes progressively greater in magnitude so as to be more detectable by the operator;
operator actuated response means for terminating said stimulus; and
, variable timing means for controlling said initiating means to initiate each stimulus following termination of the preceding stimulus after a time delay inversely related to the magnitude of the preceding stimulus upon termination.
- means for intermittently initiating successive first stimuli, each of which becomes progressively greater in magnitude so as to be more detectable by the operator;
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4. The apparatus of claim 3, further comprising:
- means for automatically initiating a second more severe stimulus when the operator actuated response means is not actuated within a predetermined time interval after initiation of each first stimulus.
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5. The apparatus of claim 4 wherein:
- said first and second stimuli are audible signals.
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6. The apparatus of claim 4 wherein:
- said stimuli initiating means includes audio frequency generating means responsive to said variable timing means for modulating the amplitude of an audio frequency signal to produce a detectable audible tone stimulus of increasing volume.
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7. A system for intermittently detecting operator alertness and for altering the repetition interval between successive stimuli in response to the detected time taken by the operator to respond to each stimulus, comprising:
- bistable switching means responsive to a stimulus initiating signal for maintaining a constant amplitude output and responsive to an operator response signal for terminating said output;
an operator response switch actuated by the operator for applying said operator response signal to said bistable switching means;
a first integrator coupled to receive said constant amplitude output for generating a fixed ramp signal of constant slope and for terminating said ramp signal to maintain a constant signal voltage equal to the maximum amplitude of said ramp signal upon termination of said constant amplitude output from said bistable switching means;
a second integrator coupled to receive the output of said first integrator to generate a parabolic output in response to said ramp signal and for generating a variable ramp output having a slope proportional to said constant signal voltage maintained by said first integrator;
comparator means coupled to receive the output of said second integrator for generating said stimulus initiating signal when the amplitude of said parabolic or variable ramp outputs from said second integrator reach a preselected threshold level;
circuit means coupled to the output of said second integrator for discharging said parabolic and ramp outputs to restore an initial zero output level in response to said initiAting signal and to said response signal; and
, means for initiating a desired stimulus to be sensed by the operator responsive to said stimulus initiating signal.
- bistable switching means responsive to a stimulus initiating signal for maintaining a constant amplitude output and responsive to an operator response signal for terminating said output;
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8. The system of claim 7, further comprising:
- alarm means for generating a severe stimulus when said operator response signal is not generated by actuation of said operator switch within a predetermined fixed time interval following each stimulus initiating signal.
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9. The system of claim 7 wherein said means for initiating a desired stimulus comprises:
- means for continuously generating an audio frequency signal capable of producing an audible tone stimulus;
amplitude modulation means responsive to the fixed ramp signal generated by said first integrator to gradually increase the amplitude of said audio frequency signal from a predetermined minimum level in accordance with the increase in the amplitude of said ramp signal; and
, gating means responsive to the constant amplitude output from said bistable switching means for selectively transmitting said audio frequency signal to said amplitude modulating means, whereby the modulated audio frequency signal provides an audible tone stimulus of increasing volume.
- means for continuously generating an audio frequency signal capable of producing an audible tone stimulus;
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10. A method for intermittently detecting operator alertness to alter operator stimuli in accordance with the detected degree of alertness, comprising the steps of:
- initiating successive intermittent stimuli detectable by the operator;
determining the time interval between the initiation of each said stimulus and the actuation of a stimulus response means by said operator; and
, delaying initiation of the subsequent stimulus for an interval inversely related to the time interval between initiation of the previous stimulus and the operator'"'"''"'"'s actuation of the stimulus response means.
- initiating successive intermittent stimuli detectable by the operator;
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11. A method for intermittently detecting operator alertness and altering the repetition rate of successive operator stimuli in response to the detected time taken by the operator to respond to the preceding stimulus, comprising the steps of:
- (step
1) generating a fixed input voltage in response to a stimulus initiation signal until terminated by an operator response signal;
(step
2) integrating said fixed input voltage to produce a ramp signal having a fixed predetermined slope;
(step
3) integrating said ramp signal to generate an increasing signal output with a gradually increasing slope;
(step
4) generating an operator response signal when a switch means is actuated by the operator;
(step
5) maintaining a constant amplitude signal voltage equal to the amplitude of said ramp signal upon generation of said operator response signal;
(step
6) discharging said increasing signal output produced by integrating said ramp signal to restore an initial zero level signal output upon generation of said operator response signal;
(step
7) integrating said constant amplitude signal voltage to generate a second ramp signal having a slope proportional to the amplitude of said constant amplitude signal;
(step
8) generating said stimulus initiating signal when the amplitude of said second ramp signal reaches a predetermined threshold level or, in the absence of an operator response signal, when the amplitude of said increasing signal output reaches said predetermined threshold level; and
, (step
9) repeating steps (1) through (8).
- (step
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12. The method of claim 11 further comprising:
- applying said ramp signal having a fixed predetermined slope to modulate the amplitude of a continuously generated audio frequency signal to gradually increase its amplitude from a predetermined minimum in accordance with the amplitude of said ramp signal;
selectively gating said continuously generated audio frequency signal to be amplitude modulated during generation of said fixed input voltage; and
, reproducing said amplitude modulated audio frequency as an audible tone of increasing volume to constitute sAid stimuli.
- applying said ramp signal having a fixed predetermined slope to modulate the amplitude of a continuously generated audio frequency signal to gradually increase its amplitude from a predetermined minimum in accordance with the amplitude of said ramp signal;
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13. An apparatus for intermittently detecting and maintaining the alertness of the driver of a vehicle without distraction from normal driving tasks, said vehicle having a steering wheel assembly within a driver compartment, comprising:
- means for intermittently initiating an audible tone stimulus of increasing volume within the driver compartment to be heard by the driver;
a pushbutton response switch mounted adjacent the steering wheel assembly of the vehicle to be manually actuated by the driver upon detection of said audible tone; and
, interval detection means responsive to the initiation of each audible tone stimulus and the actuation of said pushbutton response switch for selectively delaying initiation of each subsequent audible tone stimulus for a time period inversely related to the time interval measured between initiation of the preceding stimulus and actuation of the pushbutton response switch by the driver.
- means for intermittently initiating an audible tone stimulus of increasing volume within the driver compartment to be heard by the driver;
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14. The apparatus of claim 13 wherein a turn signal stalk is mounted on the steering wheel assembly, and wherein:
- said pushbutton response switch is mounted on the turn signal stalk extending from the vehicle steering wheel assembly.
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15. The apparatus of claim 13 further comprising:
- an audible alarm for producing a loud bell or buzzer noise within the driver compartment of the vehicle; and
, timing means responsive to the initiation of each audible tone stimulus and to the manual actuation of said pushbutton response switch for sounding said audible alarm for a fixed interval whenever said pushbutton response switch is not actuated within the determined time interval following initiation of each audible tone stimulus.
- an audible alarm for producing a loud bell or buzzer noise within the driver compartment of the vehicle; and
Specification