JPS6234215B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a device for detecting drowsy driving based on steering operation, and more particularly to a drowsy driving detection device that can perform the detection early and accurately.

[Technical Background of the Invention] Various drowsy driving detection devices have been proposed in the past for the purpose of preventing drowsy driving in pursuit of vehicle running safety. As such a drowsy driving detection device, there is, for example, the one described below. That is, in general, when drowsy driving occurs (i.e., when alertness level is decreased)
In this case, the driver's ability to correct the course is extremely low, so it is easy for the driver to remain in a non-steering state. If the driver wakes up in this state, he or she will hastily correct the course of the vehicle, and as a result, the steering speed at a certain angle of the steering wheel will change from the steering speed at a certain angle of the steering wheel caused by course correction during normal driving. There is a tendency to be faster (sudden steering) compared to . Paying attention to these points, when it is detected that the no-steering state of the steering wheel continues for a predetermined period of time and the steering speed at a certain angle of the steering wheel that occurred after the end of the no-steering state is equal to or higher than the predetermined speed, it is possible to fall asleep. Judging to be driving (Jitko Kosho 58-23713).

This device detects drowsy driving based on the steering condition when the driver momentarily wakes up and issues a warning, but since the warning is issued when the driver wakes up,
This is effective in reliably preventing future drowsy driving.

By the way, in subsequent experiments, we repeatedly measured the magnitude and steering speed of continuous one-way steering after the end of the no-steering state in the wakeful state and the low-awareness state, and considering the measurement results, it was found that the above-mentioned one Even if the steering angle of directional steering is small, if the steering speed is high, the frequency of being in the alert state is high, and as the steering angle of the unidirectional steering increases, even if the steering speed is slow, the alertness state and the alert state are more likely to occur. It turned out that it is possible to differentiate between the states.

[Objective and Summary of the Invention] The present invention has been made in view of the above, and an object thereof is to provide a drowsy driving detection device that can detect drowsy driving early and reliably.

In order to achieve the above object, the present invention provides the first
As shown in the figure, the steering angle detection means 21 detects the steering angle of the steering wheel;
a steering speed detecting means 23 for detecting the steering speed of the steering wheel based on a signal from the steering angle detecting means 2, and a steering angle change amount detecting means 2 for detecting the amount of change in the steering angle of the steering wheel based on the signal from the steering angle detecting means 21.
5, and a non-steering state detection means 2 for detecting a non-steering state based on the signal from the steering angle detection means 21.
7, a reference steering setting means 29 that sets a reference value for determining drowsy driving even at a low steering speed as the amount of change in the steering angle increases; a determination alarm that is issued when the steering speed detected by the steering speed detection means based on the detected steering angle change amount or the steering angle change amount based on the steering speed exceeds a reference value of the reference steering setting means 29; The gist is to have means 31.

[Embodiments of the Invention] Examples of the invention will be described below with reference to the drawings.

a and b in FIGS. 2 to 3 are the first
In this example, 1 is a steering angle sensor, and 5 is a microcomputer that processes the output signal of the steering angle sensor according to a flowchart described later to detect drowsy driving and drives an alarm means 7. This is a means of detecting drowsy driving. Note that the detection means includes a CPU 9, a ROM 11, a RAM 13, and an input/output port 15.

The steering speed sensor 1 has a hole 1 having a width of θ S −α and a constant interval θ _S +α in the circumferential direction, as shown in FIG. 3a _.
4' is drilled and rotates with the rotation of the steering wheel, and the rotation of the disc 18 opens the hole 14'.
Photo interrupter that turns on and off depending on the presence or absence of (Photo interrupter slits 16-1, 16-2)
width θ _F )19-1, 19-2. In addition,
The photo interrupter has a measurement minimum displacement of θ _S
/2 , n×θ _S +5θ _S /2 (n=0,
1,...). In such a configuration, the photo interrupter 19-
As shown in FIG. 3b, the outputs of 1 and 19-2 become two-phase rectangular wave signals whose phases are shifted by a constant interval θ _S /2, and are sent to photointerrupters 19-1 and 19-2 as described later. The steering direction can be determined based on changes in the output state of the steering wheel.
In FIG. 3a, reference symbol Z indicates the boundary between the presence and absence of output signals from the photo interrupters 19-1 and 19-2.

Next, the operation of this embodiment will be explained based on the processing flow of the CPU 9 shown in FIGS. 4 and 5.

First, the detection principle will be explained. In general, when the driver's level of alertness has decreased, as shown in Figure 6, the driver wakes up after no steering and tries to make hasty course corrections (see Figure 6).
(See Figure A), and a steering pulse corresponding to the steering operation is output from the steering angle sensor 1 (See Figure 6B). In other words, the output status of the steering pulse includes a no-steering region, a continuous steering in the same direction (first steering) performed after the end of the no-steering state, and a first steering performed successively after the first steering ends. is broadly divided into continuous steering in the same direction in opposite directions (second steering). In this embodiment, drowsy driving is detected by focusing on the first steering,
As a method for detecting this, a reference steering speed is set according to the steering angle of the first steering, and the determination is made based on a comparison result between the steering speed after no steering ends and this reference steering speed.

That is, as shown in FIG. 4, the process can be roughly divided into steps 50 to determine whether the preconditions for starting the detection of drowsy driving are met, step 52 to detect the non-steering state of the steering wheel and measure its time; Step 54 of determining whether a predetermined no-steering condition is satisfied; Step 56 of measuring the number of pulses from the steering angle sensor 1 and their pulse intervals due to continuous steering in the same direction (first steering) performed after the end of the no-steering condition. , a step 58 for determining whether a condition is satisfied regarding the number of measured pulses, a step 60 for determining whether a condition regarding the first steering speed calculated based on the measured pulse interval is satisfied, and an alarm step 62.

This will be explained in detail below with reference to FIGS. 5a and 5b.

First, it is confirmed that the prerequisites for starting detection of drowsy driving, such as the vehicle speed being equal to or higher than a predetermined speed (for example, 70 km/h), are satisfied, and the process proceeds to step 110 to start detecting drowsy driving. Proceed (step 100).

Proceeding to step 110, a timer A for counting the non-steering time of the steering wheel is set, and this timer time Ta and a preset non-steering time setting value _A0 are set.
(for example, 3 seconds), the system waits for input of a steering pulse while monitoring the occurrence of a no-steering state (steps 110 to 130). In this state, Ta<
If a steering pulse is input while _A0 is established, it is determined that drowsy driving has not occurred, and after clearing timer A, the process returns to step 110 (step 140). On the other hand, when Ta<A ₀ no longer holds true, it means that a no-steering condition has been established, so it is determined that there is a suspicion of drowsy driving, and the process proceeds to step 150 to clarify the suspicion.

When a steering pulse is input in step 150, the direction of the pulse is stored in the register _PFN , and then timer B is started to be driven, and the system waits for input of the next steering pulse (steps 150 to 180).
Then, when the next steering pulse is input, the direction of the relevant pulse is stored in register PF _N+1 , and then
PF _N and PF _N+1 are compared to determine whether or not both pulses are caused by steering in the same direction (steps 190-200). As a result, if the steering is in the same direction, step 210 is performed.
If not, the process proceeds to step 211 respectively.

Proceeding to step 211, the timer time Tb of the timer B is compared with the non-steering time set value _A0 . As a result, if Tb<A ₀ holds true, it is determined that no drowsy driving has occurred, and the contents of the pulse count register N, which stores the number of steering pulses related to all timers and the first steering, are set to 1 and then updated. In order to perform drowsy driving detection from the beginning, the process returns to step 110 (steps 212 and 21).
3). Further, if Tb≧A ₀ , it means that a no-steering state has occurred, and it is determined that the steering pulse determined in step 180 is not due to drowsy driving, and that the steering pulse after the end of this no-steering state Timer B is activated to newly detect drowsy driving.
After setting the contents of the pulse count register N to 1, the process returns to step 150 (step 21).
4,215).

On the other hand, when proceeding to step 210, the timer B
The timer time Tb is compared with the non-steering time set value _A0 . In this comparison, if Tb<A ₀ , it is assumed that the steering pulse input in step 180 is due to steering operation after the end of the no-steering state caused by drowsy driving, and step 240 is performed.
On the other hand, if Tb≧A ₀ , it means that a no-steering condition has occurred, and it is determined that the steering pulse input in step 180 is not due to drowsy driving, and that The timer B is reset to newly detect drowsy driving by steering the vehicle, and the content of the pulse count register N is set to 1, and the process returns to step 150.

Proceeding to step 240, the content of the pulse count register N is incremented, and the input interval time t ₁ (N) of the steering pulses input in steps 150 and 180 described above is stored, and this time value is stored in the steering speed register. The contents of TS ₁ are integrated (steps 240 to 260). and,
Based on the comparison between the value of the pulse count register N and the cumulative time (Σt ₁ (N)), a warning is issued as the shaded area in FIG. 7 is determined to be drowsy driving (steps 270 to 350).

That is, in this drowsy driving determination process, as the steering angle (value of the pulse count register N) of the first steering that is performed continuously after the end of the no-steering state increases, the reference steering speed is set accordingly. Then, if the accumulated time (Σt ₁ (N)) is within a predetermined time indicating the reference steering speed, it is determined that the driver is drowsy driving. That is, when the cumulative time is shorter than the predetermined time indicating the reference steering speed, it can be determined that the reference steering speed is exceeded. In this determination process, if none of the conditions for determining drowsy driving are satisfied, the process returns to step 170 and continues monitoring for drowsy driving. If the condition is not satisfied in step 340, it is determined that drowsy driving has not occurred, and the timer B is
After clearing the steps, the process returns to step 110 to perform drowsy driving detection from the beginning (step 36).
0).

In addition, in the above-mentioned judgment process, K ₀ , K ₁ ,
K ₂ , K ₃ , and K ₄ are reference steering angles (substituted by the value of the pulse count register N) for setting the reference steering speed, and the respective values are, for example, 3, 6, and 9, respectively. 12, 15. .
Further, K ₅ , K ₆ , K ₇ , and K ₈ are predetermined times indicating the reference steering speed, and their respective values are, for example, 0.1 sec, 0.5 sec, 1 sec, and 2 sec, respectively.

FIGS. 8 to 9 show a second embodiment of the present invention, and the circuit configuration is the same as FIGS. 2 and 3. Its characteristics include the first
For both the steering and the second steering, if the steering speed is shorter than a predetermined time indicating the reference steering speed set from the respective steering angles, it may be determined that the vehicle is drowsy driving.

That is, as shown in FIG. 8, the process outline includes Step 70 in which it is determined whether the preconditions for starting detection of driving are satisfied, and Step 7 in which the non-steering state of the steering wheel is detected and the time period thereof is measured.
2. Step 74 of determining whether a predetermined no-steering condition is satisfied; Step 76 of measuring the number of pulses from the steering angle sensor 1 and their pulse intervals during the first steering performed after the end of the no-steering state; and Step 76 of measuring the number of pulses measured. A first steering determination step 78 includes a step 78-1 for determining whether a condition is met regarding the first steering speed, and a step 78-2 for determining whether a condition regarding the first steering speed calculated based on the measured pulse interval is satisfied. Measurement step 8 of the steering pulses from the steering angle sensor 1 and their pulse intervals during the second steering subsequent to the end of the steering
0. A second steering operation consisting of a step 82-1 for determining whether a condition regarding the number of measured pulses is satisfied and a step 82-2 for determining whether a condition regarding a steering speed of the second steering operation calculated based on the measured pulse interval is established. It consists of a judgment step 82 and an alarm step 84.

A detailed explanation will be given below in FIGS. 9a to 9d.

First, it is confirmed that the prerequisites for starting detection of drowsy driving, such as the vehicle speed being equal to or higher than a predetermined speed (for example, 70 km/h), are met, and the process proceeds to step 410 to start detecting drowsy driving. Proceed (step 400).

Proceeding to step 410, a timer A for counting the non-steering time of the steering wheel is set, and this timer time Ta and a preset non-steering time setting value _A0 are set.
While monitoring the occurrence of a non-steering state by comparing the time (for example, 3 seconds), the system enters a state of waiting for input of a steering pulse (steps 410 to 430). In this state, Ta
If < _A0 is established and a steering pulse is input, it is determined that drowsy driving has not occurred, and after clearing timer A, the process returns to step 410 (step 440). On the other hand, when Ta<A ₀ no longer holds true (no steering), it is determined that there is a suspicion of drowsy driving, and the process proceeds to step 450 in order to clarify the suspicion.

When a steering pulse is input in step 450, the direction of the pulse is stored in the register _PFN , and then timer B is started to be driven, and the system waits for input of the next steering pulse (steps 450 to 480).
When a steering pulse is input, the direction of the pulse is stored in register PF _N+1 , and then register PF _N
and PF _N+1 to determine whether both pulses are caused by steering in the same direction (steps 490 to 500). As a result, if the steering is in the same direction, the process proceeds to step 510, and if not, the process proceeds to step 680.

Proceeding to step 510, the timer time Tb of the timer B is compared with the no-steering time set value _A0 . In this comparison, if Tb<A ₀ , it is assumed that the steering pulse input in step 480 is due to steering operation after the end of the no-steering state caused by drowsy driving, and the process proceeds to step 540; conversely, if Tb≧A ₀ If so, it means that a no-steering condition has occurred, and it is determined that the steering pulse inputted in step 480 is not caused by drowsy driving, and a new drowsy driving condition is detected by steering after the end of the no-steering condition. The timer B is reset as necessary, and the contents of the pulse count register N are set to 1, and the process returns to step 450.

Proceeding to step 540, the contents of the pulse count register N are incremented, the input interval time t ₁ (N) of the steering pulses input in steps 450 and 480 described above is stored, and this time value is stored in the steering speed register. The contents of TS ₁ are integrated (steps 540 to 560). and,
Based on the value of the pulse count register N and the cumulative time (Σt ₁ (N)), a timer C is set to determine that the first steering has been performed, and the shaded area in FIG. After setting the first steering detection flag X, the process returns to step 470, and then detection of the second steering is started (step 5).
70-660).

That is, in this first steering detection process, as the steering angle (value of the pulse count register N) of the first steering that continues after the end of the non-steering state increases, a reference steering speed is set accordingly. put. That is, as described above, if the cumulative time (Σt ₁ (N)) is within the predetermined time indicating the reference steering speed, it is determined that the first steering condition is satisfied.
In this judgment process, if none of the judgment conditions are satisfied, the process returns to step 470 and continues monitoring for drowsy driving. Also,
If the condition is not satisfied in step 640,
It is determined that drowsy driving has not occurred, and after clearing timer B, the process returns to step 410 to newly detect drowsy driving from the beginning (step 6).
70).

Note that the values of the reference steering angles K ₀ , K ₁ , K ₂ , K ₃ , K ₄ and the reference steering speeds K ₅ , K ₆ , K ₇ , K ₈ are the same as in the first embodiment. be.

On the other hand, when the process proceeds to step 680 based on the determination result of step 500, first the timer time of timer B is
Compare Tb with the non-steering time setting value _A0 . As a result, if Tb≧A ₀ , the no-steering condition has been newly established, so after clearing all the timers and setting the contents of the pulse count register N to 1, the process returns to step 460 to end this no-steering condition. The process starts again from the subsequent detection of the first steering (steps 690 and 700). Conversely, if Tb<A ₀ , the process proceeds to step 710.

When the process proceeds to step 710, timer B is cleared once and reset, and then enters a state of waiting for input of a steering pulse (steps 710 to 730). When a steering pulse is input, the direction of the pulse is stored in the register _PFM , and then the set state of the first steering flag X is determined. As a result, if it has not been set, it is determined in step 720 whether or not the timer time Tb of timer B set exceeds the non-steering time setting value _A0 , and if Tb< _A0 , the above-mentioned step 690 is performed. If Tb≧A ₀ , clear all the timers and set the contents of the pulse count register N and the pulse count register M that stores the number of steering pulses related to the second steering to 1 and 0, respectively. Return to step 410 (steps 760-780). That is, in this process, if X=0 and Tb<A ₀ are established, it can be determined that the driver is steering the vehicle in a reverse direction to correct the course, etc., and no drowsy driving has occurred. Drowsy driving detection starts anew from the beginning. Conversely, if it is in the set state, the process proceeds to step 790 to continue detecting the establishment of the second steering.

Proceeding to step 790, it is determined whether the steering pulse input in step 730 is due to steering in the same direction as the second steering direction. Based on this judgment result, if the steering is in the same direction, step 8 is performed.
Proceeding to step 90, the process continues to detect the establishment of the second steering operation, and if it is not due to steering in the same direction, the process proceeds to step 800.

Proceeding to step 800, the timer time Tb of timer B set in step 720 is compared with the non-steering time setting value _A0 . As a result, if Tb≧A ₀ , it means that a new no-steering condition has occurred, so all timers are cleared, the contents of pulse count registers N and M are set to 1 and 0, respectively, and the first Steering detection flag X
After resetting, the process returns to step 450 (steps 810 to 830). Conversely, if Tb<A ₀ , the process proceeds to step 840 and sets the timer time Tc of the timer C to a second steering required reference time K ₂₁ (for example, 3 seconds).

According to the comparison result in step 840, if Tc≧K ₂₁ , it is determined that drowsy driving has not occurred because the second steering was not established within the specified time K ₂₁ , and all timers are cleared. The contents of pulse count registers N and M are set to 1 and 0, respectively, and the first steering detection flag
After resetting , return to step 410 to start drowsy driving from the beginning (850 to 87).
0). On the other hand, based on the determination result in step 790, the second
If the steering pulse input during steering is in the opposite direction from the same direction, it should be determined that the driver is not drowsy driving, but for safety reasons, this is done to eliminate failure to detect drowsy driving. , a steering pulse in a direction opposite to the second steering direction input within the second steering required reference time _K21 is ignored, and a new second steering is detected subsequently. Therefore, in step 840,
If Tc<K ₂₁ holds true, the contents of the pulse count register M are cleared and the process returns to step 710 (step 880).

Proceeding to step 890, a comparison of the timer time Tb and the no-steering time setting value A ₀ shows that no steering state is established (Tb<A ₀ ), and the timer time Tc is within the second required reference time K ₂₁ After confirming that (Tc<K ₂₁ ), the process proceeds to step 910 to determine whether the second steering is established. (Steps 890, 900).
Note that in step 890, if Tb≧A ₀ , the process proceeds to step 810, and also in step 900.
In this case, if Tc≧K ₂₁ , the process proceeds to step 850.

Proceeding to step 910, the contents of the pulse count register M are incremented, and the input interval time t ₂ (M) between the steering pulse input at step 730 and the previous steering pulse is incremented.
This time value is then added to the contents of the steering speed register _TS2 (steps 910 to 93).
0). Then, based on the value of this pulse count register M and the cumulative time (Σt ₂ (M)), the first
The shaded area in Figure 0 is determined to be a drowsy driving area and a warning is issued (steps 930 to 1020).

In other words, in this drowsy driving determination process, as the steering angle (value of the pulse count register N) of the first consecutive steering operations performed after the end of the no-steering state increases, the reference steering speed is set accordingly. I'll keep it. In other words, as described above, if the cumulative time (Σt ₁ (N)) is within a predetermined time indicating the reference steering speed, it is determined that the first steering has been achieved, and after the said steering is established, the steering is performed in the opposite direction to the direction of the first steering. As the steering angle (value of the pulse count register M) of the consecutive second steering increases, a reference steering speed is set accordingly. If the cumulative time (Σt ₂ (M)) is within a predetermined time indicating the set reference steering speed, it is determined that the driver is drowsy driving. In this determination process, if none of the conditions for determining drowsy driving are satisfied, the process returns to step 710 and continues monitoring for drowsy driving. If the condition is not satisfied in step 1010, it is determined that drowsy driving has not occurred, all timers are cleared, the contents of pulse count registers N and M are set to 1 and 0, and the first steering After clearing the detection flag
0).

In addition, in the above-mentioned judgment process, K ₀ , K ₁₃ ,
K ₁₄ , K ₁₅ , and K ₁₆ are reference steering angles (substituted by the value of the pulse count register M) for setting the reference steering speed, and the respective values are, for example, 1, 3, and 6, respectively, in that order. 1, 9, and 12.

Further, K ₁₇ , K ₁₈ , K ₁₉ , and K ₂₀ are predetermined times indicating the reference steering speed, and their respective values are, for example, 1 sec, 2 sec, 3 sec, and 4 sec, respectively.

FIGS. 11 and 12 show a third embodiment of the present invention, which is characterized in that the reference steering angle and reference steering speed for determining whether the second steering operation is established are set to the reference steering angle and the reference steering speed when the first steering operation is established. The purpose is to set the reference steering angle and the reference steering speed based on the reference steering angle and reference steering speed.

That is, as shown in FIG. 11, in the first steering judgment step 78 and the second steering judgment step 82 of the processing overview of the second embodiment described above, the process is performed based on the conditions for the first steering to be established, respectively. Step 78 of setting constraint parameters (first steering detection register) for second steering establishment detection
3 and the second steering detection register determined by the first steering detection register.
Reference value selection step 82 for detecting steering establishment
Added new processing for 0.

Specifically, as shown in a to d of FIG. 12, the processing in the second embodiment described above is modified as follows. That is, when the first steering is established as a result of the determination process (steps 560 to 640) that the first steering is established, the reference steering angle (K ₀ to _{K 4} ) and reference steering speed (K ₅ to _{K 8} ) used for the establishment of the first steering are determined. ) (Steps ₅₈₅ , 605, 625, ₆₄ )
Add 5). Next, before the second steering establishment determination process (steps 940 to 1050), the set state of the first steering detection register (X ₁ to _{X 4} ) is detected, and the total value of the register value in the set state ( Σ
Xi) and the reference value K ₉ ~ _{K 11} according to the comparison result.
Process of selecting criteria for determining whether steering is established (step 9)
32-938). In addition, in accordance with the process change described above, the process related to the first steering detection flag in the second embodiment is changed to the process related to the first steering detection register in this embodiment.

Note that the circuit configuration of this example is the same as that in FIGS. 1 and 2, and is the same as that in FIGS.
In FIG. 2, steps with the same symbols as in FIGS. 8 and 9 indicate the same processing.

Furthermore, the reference values K ₉ , K ₁₀ , and K ₁₁ are, for example, 7, 4, and 1, respectively.

[Effects of the Invention] As described above, according to the present invention, a reference value is set for determining drowsy driving even at a low steering speed as the amount of change in the steering angle increases, and after the end of the no-steering state, Since a warning is issued when the steering speed based on the amount of change in steering angle or the amount of change in steering angle based on steering speed exceeds the reference value,
Drowsy driving can be detected early and reliably. That is, it is possible to detect drowsy driving with fewer false detections, so it is possible to provide a highly reliable drowsy driving warning device.

[Brief explanation of the drawing]

Figure 1 is a complaint correspondence diagram, Figure 2 and 3 are
The figures are diagrams showing the configuration of the first to third embodiments of the present invention, Figures 4 and 5 are operational flowcharts of the first embodiment of the invention, and Figure 6 is an explanation of the principle of detecting drowsy driving. 7 is a diagram showing the setting status of the judgment reference value of the first embodiment, FIGS. 8 to 9 are operation flowcharts of the second embodiment of the present invention, and FIG. Figures 11 and 12, which are diagrams showing the setting status of the judgment reference values in the embodiment, are the third embodiment of the present invention.
2 is an operational flowchart of an embodiment of the present invention. Explanation of symbols representing main parts of the figure, 21... Steering angle detection means, 23... Steering speed detection means, 25...
Steering angle change amount detection means, 27... No-steering detection means,
29... Reference steering setting means, 31... Judgment alarm means.

Claims (1)

[Scope of Claims] 1. A steering angle detection means for detecting a steering angle of a steering wheel, a steering speed detection means for detecting a steering speed of a steering wheel based on a signal from the steering angle detection means, and a steering angle detection means for detecting a steering angle from the steering angle detection means. a steering angle change amount detection means for detecting a steering angle change amount of the steering wheel based on a signal from the steering angle; a no-steering state detection means for detecting a no-steering state based on a signal from the steering angle detection means; a reference steering setting means that sets a reference value for determining drowsy driving even at a low steering speed as the steering speed increases; and a steering angle change amount detected by the steering angle change amount detection means after the end of the non-steering state. Dozing off, characterized by comprising a judgment alarm means for issuing an alarm when the steering speed detected by the steering speed detection means or the amount of change in steering angle based on the steering speed exceeds a reference value of the reference steering setting means. Driving detection device. 2. The determination alarm means is configured to determine whether the steering speed based on the amount of change in the steering angle due to consecutive steering changes in one direction after the end of the no-steering state, or the amount of change in the steering angle based on the steering speed exceeds the reference value. The drowsy driving detection device according to claim 1, is characterized in that it issues an alarm when the vehicle exceeds the limit. 3. The determination and warning means determines whether the steering speed based on the amount of change in the steering angle due to consecutive steering changes in one direction after the end of the no-steering state, or the amount of change in the steering angle based on the steering speed exceeds the reference value. A warning is issued when a steering speed based on the amount of change in the steering angle due to a reverse steering change that is subsequently made after the steering change in one direction exceeds the reference value, or when the amount of change in the steering angle based on the steering speed exceeds the reference value. A drowsy driving detection device according to claim 1, characterized in that: 4. The reference steering setting means includes a setting unit that sets lower steering speeds as first and second reference values as the amount of change in steering angle increases, and a setting unit that sets lower steering speeds as first and second reference values as the amount of change in steering angle increases; and a setting unit that sets a second reference value based on the steering speed, and the determination alarm means sets the steering speed to a second reference value based on the amount of change in steering angle due to consecutive steering changes in one direction after the end of the non-steering state. , or the amount of change in steering angle based on the steering speed exceeds the first reference value, and
A warning is issued when a steering speed based on the amount of change in steering angle due to a subsequent reverse steering change after the steering change in one direction or an amount of change in steering angle based on the steering speed exceeds the second reference value. A drowsy driving detection device according to claim 1.