JPH0622914A - Heart rate detecting device - Google Patents

Abstract

PURPOSE:To provide a heart rate detecting device which can surely detect the heart rate of a driver with high precision. CONSTITUTION:Infrared ray type heart beat sensors 11 and 12 each of which has a light projection part which is installed on a steering wheel and projects infrared rays and a light receiving part for receiving the infrared ray and detects the heart rate of a driver from the pulsation of blood are provided. Further, an electric potential type heart beat sensor 16 is provided which is installed on the steering wheel 33 and is equipped with at least two electrodes and detects the heart rate of the driver from the electric potential difference due to the pulsation between both hands, and also a heart beat data processing means 18 is provided which compares the time sequence data quantity NDI of the heart rate detected by the infrared type heart beat sensors 11 and 12 and the time sequence data NDE of the heart rate detected by an electric potential type heart beat sensor 16, and adopts a larger value as an effective heart rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heart rate detecting device used in a wakefulness determination device for determining the wakefulness of a human such as a driver of a vehicle, a ship, or a pilot of an airplane.

[0002]

2. Description of the Related Art In recent years, due to the remarkable development of road networks, the mobility of automobiles has been greatly improved, which has expanded the radius of action. Opportunities to drive cars are increasing in everyday life. When driving a car, the driver is always required to have stable physical and mental health. However, in general, the driver tends to disregard the physical condition of his or herself and, in most cases, neglect this and hold the steering wheel. Although it is desirable to drive a car within an appropriate range that suits one's physical condition, there are cases in which the user is overwhelmed without being aware of his own physical condition. If the vehicle is continuously driven for a long time without any break, the driver's fatigue accumulates, his / her health deteriorates, and his / her concentration decreases, which may cause an accident.

Therefore, conventionally, a drowsy driving warning device is provided in a vehicle to give a signal to a driver for a response at a certain time interval, and a warning is given by determining a decrease in arousal level depending on whether or not the driver's response time is appropriate. There is something I did. But,
With this conventional device, the driver may be required to respond when the driver has to concentrate on the nerves, such as when driving in the city or on a curve, or when the awakening level is not reduced, which is annoying for the driver. won.

Therefore, it is considered to prevent an accident by monitoring the driving condition according to one's own physical condition and notifying the driver of this when the appropriate driving limit is exceeded. Generally, it is known that the heart rate of the human heart increases and decreases according to driving intensity, mental tension, fear, etc. The heart rate of the driver is detected, the cycle of the heart rate is sequentially calculated and converted, and it is determined whether or not the value is within the allowable range to determine the awakening degree of the driver.

An example of a device for detecting the heart rate of a driver while driving a vehicle by using such a heartbeat sensor is disclosed in Japanese Patent Laid-Open No. 59-22537.
As an apparatus disclosed in this publication, an infrared type heartbeat sensor is provided on a steering wheel, and this heartbeat sensor has a light emitting diode as a light emitting means and a phototransistor as a light receiving means, and is generated from the light emitting diode. The light is reflected by the blood passing through the blood vessel in the driver's thumb and is incident on the phototransistor, and a light reception signal is generated at a level corresponding to the incident amount so that the change in the pulse wave of the driver is detected. ing.

Another type of heartbeat sensor is disclosed, for example, in Japanese Patent Laid-Open No. 59-25729 or 59-14429. As a device disclosed in this publication, a steering wheel is provided with an electric potential type heartbeat sensor, and this heartbeat sensor has at least two electrodes, and a period and a reference of an electrocardiographic waveform between both hands of a driver. The driver's heart rate is detected based on the number of outputs in time.

[0007]

In the above-mentioned conventional infrared type heart rate detecting device, when strong sunlight enters the passenger compartment and irradiates the phototransistor of the heartbeat sensor mounted on the steering wheel, the heartbeat is detected. There is a problem in that the sensor may malfunction and the heart rate of the driver may not be accurately detected. Also, this heart rate sensor is provided at any position on the steering wheel,
If the degree of close contact with the finger is small, external light enters through the gap between the finger and the heart rate sensor (phototransistor), and the heart rate detection accuracy decreases. Furthermore, if the finger is pressed too strongly against the heartbeat sensor, there is a problem that the blood vessels under the skin are pressed and the blood flow is disturbed, so that the heartbeat rate cannot be detected with high accuracy.

Further, in the above-mentioned conventional electric potential type heart rate detector, the driver cannot detect the heart rate unless the driver holds the steering wheel with both hands.
If the vehicle is driven continuously for a long time, the driver's fatigue accumulates, which reduces his or her concentration, weakening the grip on the steering wheel or making it difficult to grip with both hands, and steering with one hand. There is a possibility that it will be an operation, and in this case, there is also a problem that the heart rate cannot be detected.

The present invention solves such a problem, and an object of the present invention is to provide a heart rate detecting device capable of reliably and accurately detecting the heart rate of a driver.

[0010]

The heart rate detecting device of the present invention for achieving the above-mentioned object has a light emitting portion for emitting infrared rays and a light receiving portion for receiving infrared rays, which is provided on a steering wheel. An infrared type heartbeat sensor for detecting the driver's heart rate from the pulsation, and an electric potential type heartbeat sensor for detecting the driver's heart rate from the potential difference due to the pulsation between both hands, which is provided on the steering wheel and has at least two electrodes. , Comparing the time-series data number of the heart rate detected by the infrared heart rate sensor with the time-series data number of the heart rate detected by the potential heart rate sensor, and adopting the larger value as the effective heart rate And a heartbeat data processing means.

Further, according to the heart rate detecting device of the present invention, the contact of a portion of the steering wheel where the driver frequently grips and a portion of the hand having a large blood flow when the driver grips the steering wheel. A heartbeat sensor having an infrared light emitting portion and an infrared light receiving portion is provided at a position, and an elastic member is provided in the peripheral portion of the position where the heartbeat sensor is disposed, and the contact surface of the elastic member with the hand is adjusted to the partial shape of the contacting hand. And is formed to have a predetermined curvature.

[0012]

[Function] When the driver grips the steering wheel, the infrared type heart rate sensor changes the heart rate of the driver by the infrared rays projected from the light projecting part onto the driver's hand being reflected by the blood and being received by the light receiving part. On the other hand, at the same time, the electric potential type heartbeat sensor detects the driver's heart rate from the potential difference due to the pulsation of blood by the driver's both hands touching the respective electrodes, and the heartbeat data processing means is the infrared type heartbeat sensor. The time series data number of the heart rate detected by and the time series data number of the heart rate detected by the potential heartbeat sensor are compared, and the larger value is adopted as the effective heart rate.

When the driver grips the steering wheel, the portion of the hand with a large blood flow naturally contacts the infrared light emitting portion and the light receiving portion of the heartbeat sensor, and the contact portion has elasticity having a surface with a predetermined curvature. By providing the member, the degree of contact between the hand and the heartbeat sensor is increased, and the heartbeat is detected with high accuracy.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic structure of a vehicle drowsiness alarm device having a wakefulness determination device according to an embodiment of the present invention, FIG. 2 is a perspective view showing an outer appearance of a passenger compartment in this embodiment, and FIG. A graph showing the change over time of the driver's arousal level,
4 is a front view of the steering wheel, FIG. 5 is a side surface of the steering wheel, FIG. 6 is a cross section of an infrared heart rate sensor, FIG. 7 is a cross section of a wheel of the steering wheel, and FIG. 8 is another infrared heart rate sensor and potential heart rate sensor. An outline of the steering wheel, FIG. 9 is an IX-IX cross section of FIG. 8, FIG. 10 is an XX cross section of FIG. 8, FIG. 11 is an outline showing a grip state of the steering wheel by a hand, and FIG. 12 is another infrared heartbeat sensor. Outline of steering wheel represented, Fig. 1
3 is a description showing a portion with a large blood flow in the hand, FIG. 14 is a front view of a steering wheel showing another potential type heartbeat sensor, and FIG.
5 is a concept showing the relationship between the heartbeat pulse from the heartbeat sensor and the heartbeat rate data calculated by the heartbeat processing means, FIGS. 16 to 18 are flowcharts showing the flow of processing by the heartbeat processing means of this embodiment, and FIG. 20 to 22 are flowcharts showing the flow of processing by the heartbeat data processing means of the present embodiment, FIGS. 20 to 22 are flowcharts showing the flow of processing by the heartbeat / wakefulness determining means of the present embodiment, and FIG. 23 is equipped with a steering angle sensor. An extracted enlarged cross-section of the steering shaft portion, FIG. 24 is a graph showing the visual steering component of the driver with respect to the frequency distribution of the steering angle of the steering wheel, and FIG. 25 is the steering angle of the steering wheel when the driver has an upward view restriction. 26 is a graph showing the frequency distribution of FIG. 26, FIG. 26 is a schematic view showing the upper field of view of the vehicle driver, and FIGS. 29 and 30 are flowcharts showing the flow of processing by the steering alertness determination means of this embodiment, and FIGS. 31 and 32 are flowcharts showing the flow of alarm processing by the alarm control means of this embodiment. FIG. 33 is a flow chart showing the flow of processing by the handle grip failure warning processing unit of this embodiment, and FIG. 34 is a flow chart showing the flow of processing by the reference value correction unit of this embodiment.

As shown in FIGS. 1 and 2, a pair of left and right infrared type heartbeat sensors 11 and 12 respectively detecting heartbeat pulses of a driver (not shown) are provided with detection signals from the infrared type heartbeat sensors 11 and 12. The heartbeat processing means 13, 14 for receiving and calculating the heart rate of the driver are connected, and the heartbeat processing means 13, 14 are connected to the heartbeat processing means 13, 14.
The signal selecting means 15 which adopts the more preferable output signal among the output signals from 4 is connected. Further, a potential type heartbeat sensor 1 different from the above-mentioned heartbeat sensors 11 and 12
The heartbeat processing means 17 for receiving the detection signal from the potential type heartbeat sensor 16 and calculating the heart rate of the driver is connected to the reference numeral 6, and the signal selecting means 15 and the heartbeat processing means 17 are connected.
The heartbeat data processing means 18 for calculating the average value of the heart rate and its change state based on the output signals from the signal selecting means 15 and the heartbeat processing means 17 is connected to the heartbeat data processing means 18. Heartbeat data processing means 1
The heartbeat / wakefulness determination means 19 for determining the awakening degree of the driver based on the calculation result from 8 is connected.

On the other hand, a steering angle sensor 21 for detecting a deviation from the neutral position of the steering shaft 20 (hereinafter referred to as steering angle) is subjected to frequency analysis by receiving a detection signal from the steering angle sensor 21. The steering angle data processing means 22 for calculating the parameter of the steering component is connected to the steering angle data processing means 22.
The steering alertness determination means 23 for determining the alertness of the driver based on the calculation result from is connected. Further, the steering angle data processing means 22 in the present embodiment is also connected to a vehicle speed sensor 24 for detecting a traveling speed of the vehicle (hereinafter, referred to as vehicle speed), and a detection signal from the vehicle speed sensor 24 also serves as a steering angle. It is designed to be taken into the data processing means 22.

Further, in the vehicle of this embodiment, a tactile alerting means 26 for issuing a drowsiness alert by deformation of the driver's seat 25, a visual alerting means 28 for transparently displaying the drowsiness alert on the front window 27 of the vehicle, and a drowsiness alert sound. And an audible alarm means 29 for emitting the alarm are provided.
The alarm control means 30 for controlling the operations of 6, 28 and 29 includes
The heartbeat alertness determination means 19 and the steering alertness determination means 2
3 is connected, and the alarm level selected by the heartbeat / wakefulness determination means 19 and the steering / wakefulness determination means 23, data relating to the driver's awakening degree, and the like are output to the warning control means 30. Awakening degree determination means 19
And, based on the alarm level selected by the steering alertness determination means 23, the operation of each of the three alarm means 26, 28, 29 is controlled.

Further, an alarm release switch 31 for the driver to release the above-mentioned alarms by the operation of the three alarm means 26, 28, 29 is provided in the vehicle compartment. The alarm control means 30 and the reference value correction unit 32 are connected. Then, the heartbeat awakening degree determining means 19 and the steering awakening degree determining means 23 are connected to the reference value correcting section 32, and the data calculated by the reference value correcting section 32 are the heartbeat awakening degree determining means 1.
9 and the steering alertness determination means 23.

In the present embodiment, the above-mentioned two types of heart rate sensors 11, 12, 16 are attached to the steering wheel 33 at predetermined positions, so that the driver can grasp the steering wheel 33 at a predetermined position with both hands. If it is not, in particular, the potential type heart rate sensor 16 cannot detect the heartbeat pulse. Therefore, a mechanism for urging the driver to properly grasp the steering wheel 33 is also incorporated.

That is, the vehicle of this embodiment has the alarm control means 3
0 is provided with a handle grip failure alarm means 34, and in this embodiment, two of the above three alarm means 26, 29 are used as the handle grip failure warning means 34. There is. Further, the heartbeat processing means 13, 14, 17 are provided in the alarm control means 30.
The steering wheel grip failure alarm processing unit 35 that receives the output signal from the steering wheel 33 is incorporated in the steering wheel steering wheel 33 based on the output signals from the heartbeat processing means 13, 14, and 17. If it is determined that the driver does not properly grip the steering wheel 33, the steering wheel grip failure warning means 34 is activated, while the driver correctly grips the steering wheel 33. If it is determined that the steering wheel is not properly gripped, the operation of the steering wheel grip failure warning means 34 is automatically stopped.

By the way, it is well known that the driver's arousal level generally tends to gradually decrease immediately after boarding, but the vehicle runs for a long time on a monotonous road or a motorway in the suburbs where there is no congestion. In many cases, a remarkable decrease is seen. An example of such changes over time of the driver's arousal level is shown in the form of a graph in FIG. That is, the area of represents the time until getting into the vehicle by walking or the like, represents the area of decrease in arousal level due to sitting on the driver's seat 25, and represents the area of increase in arousal level due to tension immediately after the start of travel or during urban driving. The area of, represents the area where the arousal level is stable while driving on a monotonous road or a car-only road that is not congested, and the area of the represents the area where the driver's arousal level goes up and down and the drowsiness conflict, It represents the area where the degree of arousal decreased and the person fell asleep.

As is apparent from FIG. 3, there is usually an area in which the driver's awakening level rises and falls and a conflict with the drowsiness occurs before the drowsiness state of the driver. Generally, there is a region where the driver's arousal level stabilizes before the conflict condition. In other words, the driver's arousal level is continuously monitored to estimate a stable region of the arousal level, and from this stable region of the arousal level, the driver's arousal level is expected to be a conflict area with the drowsiness, which relatively rises and falls, By issuing an alarm here, it becomes possible to prevent the driver from falling asleep.

Based on such knowledge, the two types of heart rate sensors 11, 12, 16 for changing the arousal level shown in FIG. 3 are described above.
Are estimated based on the detection signal from the two types of heart rate sensors 11, 12, 16 in the present embodiment.
Are incorporated in predetermined positions of the steering handle 33.

The infrared heart rate sensors 11 and 12 which function independently of each other are designed to detect the pulsation of blood flowing through blood vessels by infrared rays, paying attention to the high reflectance of hemoglobin in blood to infrared rays. is there. Further, the potential type heartbeat sensor 16 is adapted to detect a pulsed potential difference between both hands of the driver, which is generated due to pulsation of blood. In this embodiment, the infrared heartbeat sensors 11 and 12 may malfunction when exposed to strong sunlight, while the potential heartbeat sensor 16 does not hold the steering wheel with both hands of the driver. In this case, since the heart rate cannot be detected, the two heart rate sensors 11, 12, 16 are combined so that the heart rate of the driver can be reliably detected.

As shown in FIGS. 4 and 5, the steering wheel 33 is rotatably mounted on the steering column 36 and is composed of the steering shaft 20, the hub 51 and the circular wheel 52. The infrared heart rate sensors 11 and 12 and the potential type heart rate sensor 16 are connected to the wheel 52 of the steering wheel 33.
Installed on.

The infrared heart rate sensors 11 and 12 are composed of an infrared light emitting diode 61 serving as a light emitting portion and a phototransistor 62 serving as a light receiving portion, and a position where the driver naturally grips the steering wheel 33 with his left and right hands, For example, the hand of the clock with respect to the steering wheel 33 is at 10 o'clock 1
They are attached at two positions indicating 0 minutes, and an angle α formed by a straight line extending from the center of the steering wheel 33 to each heartbeat sensor 11, 12 is approximately 120 degrees.

That is, in the infrared heart rate sensors 11 and 12, as shown in FIG.
A housing 63 made of a resin member is embedded in the housing 2, and the infrared light emitting diode 6 is housed in the housing 63.
1 and the phototransistor 62 are attached. A visible light cut filter 64 is fixed to the outer surface of the phototransistor 62, and a cover 66 is fixed to the outer surface of the housing 63 excluding the infrared light emitting diode 61 and the phototransistor 62 via a rubber 65. ..

On the other hand, as shown in FIGS. 4 and 5, the potential type heart rate sensor 16 includes a pair of electrodes 67, 68 provided on both sides of the wheel 52 of the steering wheel 33 along the circumferential direction.
It consists of That is, as shown in FIG. 7, the wheel 52 of the steering handle 33 is formed by mounting a urethane foam 54 or the like around a small-diameter rim 53. 33
Three recesses are formed along the circumferential direction, and electrodes 67 and 68 are attached to the recesses, respectively.

Further, a controller 69 is mounted in the hub 51 of the steering wheel 33, the infrared light emitting diode 61 and the phototransistor 62 of the infrared heartbeat sensors 11 and 12 are connected, and the potential heartbeat sensor 1 is also connected.
Six pairs of electrodes 67 and 68 are connected.

Therefore, in this embodiment, when the driver naturally grips the steering wheel 33, the left and right palms come into contact with the pair of electrodes 67 and 68 of the potential type heartbeat sensor 16, and
The thumb contacts the infrared light emitting diode 61 and the phototransistor 62 of the infrared heart rate sensors 11 and 12. At this time, as shown in FIG. 6, the infrared ray heart rate sensors 11 and 12 cause infrared rays emitted from the infrared light emitting diode 61 to reflect on the hemoglobin in the blood of the blood vessel 70 and enter the phototransistor 62, whereby the blood vessel 70 is irradiated. The pulsation of blood flowing through is detected. Further, the potential type heartbeat sensor 16 detects a pulsed potential difference between the two hands of the driver caused by the pulsation of blood from the pair of electrodes 67 and 68, and detects the pulsation of the heart.

The mounting structure of the infrared heartbeat sensors 11 and 12 and the electric potential type heartbeat sensor 16 to the steering wheel 33 is not limited to the above-mentioned embodiment. 8 to 11 show another embodiment.

As shown in FIG. 8, the infrared heart rate sensor 1
Reference numerals 1 and 12 are composed of an infrared light emitting diode 61 and a phototransistor 62, and are mounted at two positions where the driver naturally holds the steering wheel 33 with his left and right hands. That is, as shown in FIGS. 9 and 10, on the wheel 52 of the steering handle 33, a cover 71 made of a resin member is attached at a predetermined position in the circumferential direction so as to project inward, and infrared light is emitted to the cover 71. Diode 6
1 and the phototransistor 62 are fixed side by side. The cover 71 is filled with an elastic member 72 such as silicon to hold the infrared light emitting diode 61 and the phototransistor 62.

In addition, in the elastic member 72 filled in the cover 71, a portion of the contact surface with which the thumb comes into contact has a predetermined curvature C ₁ corresponding to the shape of the touching thumb so that the degree of close contact between the two becomes high. , C ₂ , C ₃ are set. As shown in FIG. 11, the direction in which the infrared light emitting diodes 61 and the phototransistors 62 are lined up is an angle formed by the fingertip direction of the thumb and the circumferential direction of the steering wheel 33 when the driver grips the steering wheel 33. Are set along the direction of β. In the embodiment, the case of the right hand is shown, but the same applies to the case of the left hand.

On the other hand, as shown in FIGS. 8 and 10, the electric potential type heart rate sensor 16 includes the wheel 52 of the steering wheel 33.
A pair of electrodes 67 and 68 are provided on both sides of the electrode along the circumferential direction.

Therefore, in the present embodiment, the infrared heart rate sensors 11 and 12 are provided at the part where the thumb contacts when the driver naturally grips the steering wheel 33, and the contact surface where the thumb contacts the thumb. Since the elastic member 72 having a curvature corresponding to the shape is provided, the driver's thumb easily fits on the heart rate sensors 11 and 12 and is less likely to be affected by external light. , 12
The degree of adhesion with can be increased. Further, in this embodiment, since the elastic member 72 can absorb the variation in the pressing force of the fingertip, it is possible to prevent the disturbance of the blood flow under the skin, and thus the signals detected by the heartbeat sensors 11 and 12 are illustrated. The heart rate can be accurately detected from the signal after being amplified by the amplified signal conversion unit, and the abnormality based on the rhythm pattern can be detected with high accuracy.

Further, FIGS. 12 and 13 show another embodiment of the mounting structure of the infrared heartbeat sensor. In this embodiment, as shown in FIG. 12, three infrared heartbeat sensors 11 and 12 are provided on the left and right sides of the steering wheel 33. As shown in FIG. 13, the portion of the hand where the blood flow is large is the first portion 75 of the thumb, the second portion 76 of the palm, and the third portion 77. And the steering wheel 3 corresponding to the first to third parts 75, 76, 77 of this hand
An infrared heart rate sensor 11 is provided at each of the three positions.

Therefore, even if there is a slight difference in the position and form of grip of the steering wheel 33 due to individual differences among drivers, the three infrared heart rate sensors 11 eliminate detection errors and reliably detect the heart rate of the driver. it can.

FIG. 14 shows another embodiment relating to the potential heartbeat sensor. In this embodiment, as shown in the figure, the potential heartbeat sensor 16 is covered by electrodes 8 so as to cover the wheels 52 on the left and right sides of the steering wheel 33.
1 is formed and attached. Therefore, the wearability is better than that of the electrode-embedded type.

The heartbeat processing means 13 and 14 calculate the heart rate of the driver based on the detection signals from the infrared type heartbeat sensors 11 and 12. Similarly, the heartbeat processing means 17 is a potential type. The heart rate of the driver is calculated based on the detection signal from the heart rate sensor 16. The calculation contents of the heartbeat processing means 13, 14 and 17 are basically the same, and the heartbeat pulse interval (hereinafter referred to as pulse interval) and this pulse are obtained by appropriately correcting the abnormal detection signal. The heart rate corresponding to the interval is calculated.

As shown in FIG. 15, which shows an example of the relationship between the heart rate data calculated by the heartbeat processing means 13, 14, 17 and the heartbeat pulse detected by the heartbeat sensor,
For example, if the pulse interval suddenly becomes shorter than the pulse interval measured up to that point, the heart rate calculation operation based on the pulse interval at this time is temporarily suspended, and the next measured pulse interval and the previous If the sum of the pulse intervals of the above is substantially the same as the pulse intervals up to then, it is judged that the previous heartbeat pulse information is abnormal, and the previous heart rate data is canceled. For example, time t _{P (n-4)} and subsequent time t _{P (n-3)}
If the pulse intervals I _{P (n-4)} and I _{P (n-3) at} are abnormally shorter than the previous pulse intervals I _P , the heart rate calculated at time t _{P (n-4)} Hold these two pulse intervals I
_If the value obtained by adding _{P (n-4)} and I _{P (n-3)} is almost equal to the pulse interval I _P up to that point, it was determined that the heartbeat pulse at time t _{P ( n-4)} was noise. The determination is made and the heart rate data at this time t _{P (n-4)} is canceled. Also, when the pulse interval suddenly becomes longer, if the next measured pulse interval is almost the same as the previous pulse interval, the pulse interval two times before was calculated for half the time of the previous pulse interval. It is added to the time and the heart rate data at this point is interpolated. For example,
If the time t _{P (n-1)} pulse interval in I _{P (n-1)} is abnormally longer than the pulse interval I _P up before that, at the time the next heartbeat pulse is detected t _{P (n)} pulse interval I _{P (n)} when almost the same as the previous pulse interval I _P, it is determined that it could not be detected in normal heartbeat pulse between the second last and the last, the last pulse interval I _{P (n-1 )} Is added to the time t _{P (n−2)} when the heartbeat pulse _two times before is detected, and the heart rate at this time is calculated.

The flow of processing in the heartbeat processing means 13, 14, 17 is shown in FIGS. That is, the processing of the heartbeat processing means 13, 14, 17 in this embodiment is performed every predetermined period, for example, every interrupt signal every 15 milliseconds. First, in the step a1, the heartbeat sensors 11, 12, 1 are processed.
The detection time t _P of the heartbeat pulse which is the detection signal from 6 is read, and the detection time t of the current pulse is detected in step a2.
_The previous pulse detection time t _{P (n-1)} is subtracted from _{P (n)} to calculate the current pulse interval I _{P (n)} based on the following equation. I _{P (n)} = t _{P (n)} −t _{P (n-1)}

[0043] Then, it is determined whether the pulse interval reference value I _PB is set at a3 step, initially the pulse interval reference value I _PB is not set, the process proceeds to step a4 It is determined whether the pulse interval I _{P (n)} is between a preset minimum pulse interval I _MN , for example 600 ms and maximum pulse interval I _MX , for example 1200 ms.

In step a4, the pulse interval I _{P (n)}
Is not between the minimum pulse interval I _MN and the maximum pulse interval I _MX , that is, the pulse interval I calculated in step a2.
If it is determined that _{P (n)} is abnormal, the process proceeds to step a1 again after the interrupt signal of the above-described predetermined period. Further, in the step of a4, the pulse interval I _{P (n)} is between the minimum pulse interval I _MN and the maximum pulse interval I _MX ,
That pulse is calculated in step a2 interval I _{P (n)} if it is determined that the normal value at the calculated step pulse interval I _P a _(n) a5 in step a2 reference pulse is adopted as the interval I _PB, the reference pulse interval I _PB and preset additional time T _a at a6 step, for example, than the sum of the 250 msec time pulse interval I _{P (n)}
Is long or not. Even if it is determined in step a3 that the reference pulse interval I _PB is set, the process proceeds to step a6.

At the step a6, the reference pulse interval I
_The current pulse interval I _{P (n)} is shorter than the sum of _PB and the preset addition time T _A , that is, the current calculated pulse interval I
If it is determined that the value of _{P (n)} is not abnormal, then in step a7, the pulse interval is smaller than the value obtained by subtracting a preset subtraction time T _S from the reference pulse interval I _PB , for example, 250 milliseconds. It is determined whether I _{P (n)} is short, and in this step a7, the pulse interval I _{P (n)} is less than or equal to the value obtained by subtracting the preset subtraction time T _S from the reference pulse interval I _PB .
When it is determined that there is a possibility of abnormality in the value of the pulse interval I _{P (n)} calculated this time, it is determined in step a8 whether or not a heart rate data hold flag F _R described later is set. To do.

In step a8, the heart rate data holding flag F _{R, which} will be described later, is set, that is, the value of the previously calculated pulse interval I _{P (n-1)} may be abnormal. If the determination is determined to be pending, the processing proceeds to step a9, the current pulse interval I _{P (n)} as the current pulse interval I _{P (n)} and the previous pulse interval I _{P (n-1)} Is added to the corrected pulse interval I _{P (n)}
There again determines in reference pulse interval I is OR or less whether the a10 steps of the value or more that is obtained by subtracting a subtraction time T _S from _PB and the reference pulse interval I _PB and the additional time T _A. Further, in step a8, the heart rate data holding flag F _R is not set, that is, the previously calculated pulse interval I _{P (n-1)} is normal and the current pulse interval I
If it is determined that the value of _{P (n)} is abnormal, the process proceeds to step a11 to set the heart rate data holding flag F _R , and further at step a12, a first input failure determination flag F described later. _U1 and the second input failure determination flag F _U2 and the input normality determination flag F _NI are reset, and the processing after the step a1 is repeated following the next interrupt signal.

[0047] The pulse interval is set at step a9 I _{P (n)} is the reference pulse interval I _PB and preset subtraction time T _S the subtracted value or more from the reference pulse interval I _PB and the preset additional time was If it is equal to or less than the sum of T _A , that is, if the previous pulse interval I _{P (n-1)} is abnormal in step a10, the process proceeds to step a13 and the heart rate data holding flag F is entered. Reset _R. Then, based on the pulse interval I _{P (n)} corrected in step a9, the current heart rate R _{H (n)} is calculated by the following equation (1) in step a14, and in step a15. It is determined whether or not the count-up of the heart rate data timer has started. R _{H (n)} = 60 / I _{P (n)}

If it is determined in step a15 that the heart rate data timer has not started counting up, in step a16 the heart rate data timer starts counting up, and in step a17. After incrementing the heart rate data number N _D by one, the pulse interval I _{P (n)} set in step a9 is adopted as a new reference pulse interval I _{PB in} step a18, and the pulse interval I _PB After the interrupt signal, the process proceeds to step a1 again.

On the other hand, in step a6, the pulse interval is
I_{P (n)}Is the reference pulse interval I_PBAnd the preset addition time T
_AIs equal to or greater than the sum of the
If it is determined that missing of a space is expected,
The first input failure determination flag F after shifting to step_U1Set
Then, an input normality determination flag described later in step a20
F_NIIs set, and if a20
Input normality determination flag F described later in step_NISet
Yes, that is, the previous input was normal
In this case, proceed to step a21 and enter
The pulse interval I already set as the initial time of the imager_{P (n)}
Set, start counting up from here, and
In step 22 of this, the input failure accumulation timer
Value T _CIIs a preset time T_RI, For example from 3 seconds
Is also long.

When it is determined in step a22 that the count value T _CI by the input failure integration timer is less than or equal to the set time T _RI , the process proceeds to step a1 after the above-mentioned interrupt signal of a predetermined cycle. . Also, in the step of a22, the count value T _CI by the input failure integration timer is
_{Exceeds the} set time T _RI , that is, when it is determined that the heartbeat pulse data read in the step a1 is continuously abnormal, the heart rate data number N _D is set to 0 in the step a23. Then, in step a24, the count value T _CR of the heart rate data timer is reset to 0, and in step a25, the count-up of the input failure integration timer is reset. The process proceeds to step a1 again.

[0051] Also, the input normal determination flag F _NI determined in step a20 is not set, that is, if it is determined that the previous input is abnormal, the input defect integrating timer proceeds to step a26 It is determined whether or not the count-up is started, and if it is determined in step a26 that the count of the input failure integration timer is started, the process proceeds to step a22 described above. On the contrary, if it is determined in step a26 that the counting of the input failure integration timer has not started, the counting of the input failure integration timer is started in step a27, and then the predetermined period Following the interrupt signal, the process again moves to step a1.

The pulse interval I _{P (n)} set in step a9 is shorter than the value obtained by subtracting the subtraction time T _S from the reference pulse interval I _PB , or this pulse interval I _{P (n)} is the reference. Longer than the sum of the pulse interval I _PB and the addition time T _A ,
That is, if the pulse interval I _{P (n)} corrected this time is also abnormal, a1
If the determination is made in step 0, the process moves to step a28 to set the second input failure determination flag F _U2 ,
Also, in step a29, the first input failure determination flag F _U1
After resetting the input normality determination flag F _NI and the heart rate data holding flag F _R , and starting counting up of the input failure integration timer in step a30,
Subsequent to the interrupt signal of the above-mentioned predetermined period, the process again moves to step a1.

[0053] Further, the pulse interval I _{P (n)} is longer than the value obtained by subtracting the subtraction time T _S from the reference pulse interval I _PB at a7 step, i.e. currently calculated pulse interval I _{P (n)}
When it is determined that the normal input determination flag F _NI is used, the normal input determination flag F _NI used in the determination step a20 is set, and the second input failure determination flag F _U2 is set in the step a32. It is determined whether or not is set. Then, if it is determined in step a32 that the second input failure determination flag F _U2 is set, that is, if an abnormal heartbeat pulse is detected twice in succession, the process proceeds to step a33 and the input failure occurs. The count value T _CI of the integration timer is reset to 0, and the heart rate data number N _D is reset to 0 in step a34, and further, a3
Heart rate data timer count value T _{CR in} step 5
After resetting to 0, the process proceeds to step a14.

On the other hand, when the second input failure determination flag F _U2 is not set in the step a32,
At step a36, it is determined whether or not the first input failure determination flag F _U1 is set, and this a3
If it is determined in step 6 that the first input failure determination flag F _U1 is set, that is, if the previously calculated pulse interval I _{P (n-1)} is too long, then step a37. Then, it is determined whether or not the count value T _CI of the input failure integration timer is larger than the set time T _RI . When it is determined in step a36 that the first input failure determination flag F _U1 is not set, the above-mentioned a
Go to step 14.

When it is estimated that the count value T _CI of the input failure integration timer is equal to or less than the set time T _RI in step a37, that is, there is an undetected heartbeat pulse between the previous time and the last time before. Performs the processing of the heartbeat data interpolation of the heartbeat pulse that was not calculated between the previous time and the previous two times in the step of a38, and further resets the first input failure determination flag F _U1 in the step of a39 to Go to step.

If the count value T _CI of the input failure integration timer is longer than the set time T _RI in step a37, that is, if the previously calculated pulse interval I _{P (n-1)} is abnormally long. If it is determined that the pulse is not a normal heartbeat pulse, the process proceeds to step a40 and the heart rate data number N
_After resetting _D to 0, further resetting the count value T _CR of the heart rate data timer to 0 in step a41 and resetting the count value T _CI of the input failure integrating timer to 0 in step a42, Following the interrupt signal of the predetermined cycle, the process again moves to step a1.

The heart rate data calculated by the heart rate processing means 13 and 14 should be basically the same, but if the heart rate data is different for some reason, the control is safe. Considering this, the signal selecting means 15 adopts one of the two heartbeat processing means 13 and 14 which outputs a large heartbeat rate, and outputs it to the heartbeat processing means 18. Since the two infrared type heart rate sensors 11 and 12 are used in the present embodiment, an accurate heart rate can be calculated even when the steering wheel 33 is held by one of the left and right hands. In this case, it goes without saying that the output from the heartbeat processing means that outputs the normal heartbeat rate data is adopted.

Since the heartbeat data processing means 18 considers the periodic fluctuation of the heart rate associated with the breathing motion of the driver, the heartbeat is around 3 to 5 during one breathing motion at rest. In the present embodiment, an average value of the heart rate data of the past four times (hereinafter, referred to as a four-point moving average heart rate) is calculated, and the variation of the heart rate due to the breathing of the driver is smoothed.
In addition, based on the 4-point moving average heart rate of this time, the last time, and the time before last, it is determined whether the previous 4-point moving average heart rate is a polar heart rate that changes from an upward trend to a downward trend or from a downward trend to an upward trend. Or calculate. Then, the inclination between the adjacent pole heart rates obtained by dividing the deviation of the adjacent pole heart rates by these time intervals is calculated, and the average value of the heart rate data of the past 10 times (hereinafter, 10 points are calculated). A moving average heart rate) and a simple average value of the heart rate for the past 30 seconds (hereinafter,
This is referred to as a 30-second average heart rate).

FIG. 19 shows the flow of processing in the heartbeat data processing means 18 in this embodiment. That is,
In step b1, it is determined whether or not the heart rate data number N _DI from the signal selecting means 15 is equal to or more than the heart rate data number N _DE from the potential heart rate sensor 16, and in the step b1 the signal selecting means 15 When it is determined that the heart rate data number N _DI from the electric potential type heart rate sensor 16 is equal to or more than the heart rate data number N _DE from the potential type heart rate sensor 16, the process proceeds to step b2 and the signal selecting means 15 is set as the effective heart rate data number N _DA. Heart rate data number N from one of the infrared heart rate sensors 11 and 12 via the
_DI is adopted, and in step b3, it is determined whether or not this effective heart rate data number N _DA is 4 or more, which is the number of data required to calculate the 4-point moving average heart rate R _A4 .
If it is determined in step b1 that the heart rate data number N _DI from the signal selecting means 15 is smaller than the heart rate data number N _DE from the potential type heart rate sensor 16, the process proceeds to step b4. As the effective heart rate data number N _DA , the heart rate data number N _DE from the potential heart rate sensor 16 is adopted,
Go to step b3.

In step b3, the effective heart rate data number N
When it is determined that _DA is 4 or more, the 4-point moving average heart rate R _{A4 (n)} is calculated in the step b5, and the pole index of the 4-point moving average heart rate R _A4 is further calculated in the step b6. M _AI
Is calculated based on the following equation, and then it is determined in step b7 whether or not the pole index M _AI is 0 or less. In addition,
If it is determined in step b3 that the number N _{DA of} effective heart rate data is less than 4, then 4 in step b5
Since the point moving average heart rate R _{A4 (n)} cannot be calculated,
Return to step b1 again. M _AI = { _{RA4 (n)} -RA4 _(n-1) } · { _{RA4 (n-1)} -R
_{A4 (n-2)} }

In step b7, the pole index M _AI is 0.
It is the following, that is, the same value only for this time and the previous time, the same value only for the time before and the time before last, or the previous four-point moving average heart rate R _{A4 (n-1)} is larger than this time 4-point moving average heart rate R _{A4 (n-2)} greater than this time, or this time 4 points moving average heart rate R _{A4 (n-1)} greater than 4 points before last 4 points moving Average heart rate R
If it is determined that _{A4 (n-2)} is larger, the process proceeds to step b8, and as the extreme heart rate R _{HP (n)} , the previous four-point moving average heart rate R _{A4 (n- 1)} is adopted, and in step b9, the pole index M _PI of the pole heart rate R _HP is calculated based on the following formula, and it is then determined in step b10 whether or not the pole index M _PI is smaller than 0. To judge. M _PI = {R _{HP (n)} −R _{HP (n-1)} } · {R _{HP (n-1)} −R
_{HP (n-2)} }

Then, in step b10, the pole index M
_PI is less than 0, that is, the previous extreme heart rate R _{HP (n -1)} is larger than the current extreme heart rate R _{HP (n)} and the previous extreme heart rate R _{HP (n-2),} or If it is determined to be smaller Conversely, the process moves to b11 step to register the previous peak point heartbeat rate R _{HP (n-1),} further peak point heartbeat rate was last registered in b12 step R _{HP (n -2)} and the difference between the extreme heart rate R _{HP (n-1)} registered this time are divided by these times to calculate the slope D _RH , and then in step b13, the effective heart rate data number N _DA Is 10 or more, which is the number of data required to calculate the 10-point moving average heart rate R _A10 , is determined. In the step b10, the pole index M _PI
Is 0 or more, that is, it is judged that the previous extreme heart rate R _{HP (n-1)} is the same as this time or the time before last, or the magnitude of the extreme heart rate R _HP is arranged in the order of this time, last time, last time before. In this case, go to step b13
After resetting _{HP (n-1)} without registering, the process proceeds to step b14. Also, in the step b7, the pole index M
_AI exceeds the 0, i.e. 4-point running average size of the heart rate R _A4 is now the last, because arranged in the order of the second last four points of the previous running average heartbeat rate R _{A4 (n -1)} is pole Even when it is determined that the heart rate is not detected, the process proceeds to step b14.

In step b14, the number of effective heart rate data
N_DAIf it is judged that there is 10 or more, the
10 points moving average heart rate R_{A10 (n)}Calculate
Then, in step b16, the heart rate data timer is counted.
Value T_CRIs 30 seconds or more. B above
Effective heart rate data number N in 13 steps_DAIs less than 10
If it is determined that
10-point moving average heart rate R _{A10 (n)}Cannot be calculated, so
The procedure returns to step b1 described above.

When it is determined in step b16 that the count value T _CR of the heart rate data timer is 30 seconds or more, the average heart rate R for 30 seconds is 30 seconds in step b17.
_{A30 (n)} is calculated, and the process returns to step b1 described above. or,
In step b16, the count value T _CR of the heart rate data timer is less than 30 seconds, that is, the 30-second average heart rate R
If it is determined that _{A30 (n)} cannot be calculated,
Return to step b1 again.

The heartbeat / wakefulness determining means 19 determines whether the fluctuation of the heart rate calculated by the heartbeat data processing means 18 is stable, that is, the fluctuation range of the 4-point moving average heartbeat within a predetermined time, for example, 30 seconds. A state within a predetermined value, for example, 2 is determined as the driver's awakening stable region shown in FIG. 3, and the 30-second average heart rate R in this awakening determination region is determined.
While calculating _A30 as the reference heart rate, the heartbeat data processing means 1 after determining that the driver is in the awakening stable region
When the extreme heart rate R _HP calculated in 8 appears to be slightly smaller than the reference heart rate, the driver determines that it is in the conflict area of FIG. 3, and then the reference heart rate and the current driving The driver's heart rate data to determine the driver's arousal level,
The alarm level corresponding to this arousal level is set.

20 to 22 show the flow of processing in the heartbeat / wakefulness determining means 19 in this embodiment. That is, the processing of the heartbeat / wakefulness determination means 19 in the present embodiment is performed every predetermined period, for example, every 15 millisecond interrupt signal. First, at step c1, the conflict state experienced flag _FST is set. Whether or not there is a conflict state experienced flag F _ST is not set at first, so the process proceeds to step c2, and it is determined whether or not the count value T _CR of the heart rate data timer is 30 seconds or more. If it is determined in step c2 that the count value T _CR of the heart rate data timer is 30 seconds or more, that is, the heart rate data is normal for 30 seconds or more, c
In step 3, the absolute value of the value obtained by subtracting the 10-point moving average heart rate R _{A10 (n)} from the 30-second average heart rate R _{A30 (n)} calculated by the heart rate data processing means 18 is 2 or less. Or not. When it is determined in step c2 that the count value T _CR of the heart rate data timer is shorter than 30 seconds, that is, the above-mentioned 30-second average heart rate R _{A3 0 (n)} cannot be calculated. , And the steps after c1 are repeated based on the next interrupt signal.

Average heart rate R for 30 seconds in step c3
_When it is determined that the absolute value of the value obtained by subtracting the 10-point moving average heart rate R _{A1 0 (n)} from _{A30 (n)} is 2 or less, that is, there is almost no fluctuation in the driver's heart rate, c4 In the step of, from the current extreme heart rate R _{HP (n)} to the previous extreme heart rate R
It is determined whether or not the absolute value of the value obtained by subtracting _{HP (n-1)} is less than 2, and at the step c4, the current extreme heart rate R
_When it is determined that the absolute value of the value obtained by subtracting the previous pole heart rate R _{HP (n-1 )} from _{HP (n)} is less than 2, that is, the fluctuation state of the pole heart rate R _HP is relatively gentle. Determines whether the pole heart rate timer has started counting up in step c5. In this case, since the pole point heart rate timer has not started counting up at first, the process moves to step c6 to start counting up the pole point heart rate timer, and then at step c7, the current pole point heart rate R
It is determined whether the absolute value of the slope D _RH between _{HP (n)} and the previous extreme heart rate R _{HP (n-1)} is less than 1. Also, when it is determined in step c5 that the extreme heart rate timer has started counting up, the process proceeds to step c7.

Then, in step c7, it is determined that the absolute value of the slope D _RH of the adjacent pole heart rate R _HP is less than 1, that is, the pole heart rate R _HP is rising or falling very gently. In that case, the process proceeds to step c8, and it is determined whether or not the count-up of the extreme heart rate gradient timer is started. In this case, since the count of the pole heart rate slope timer is not started at first, the process shifts to step c9 to start the count of the pole heart rate timer, and then the count of the pole heart rate timer is counted in step c10. It is determined whether or not the value T _CP is a preset time T _RP , for example, 30 seconds or more. Also, when it is determined in step c8 that the extreme heart rate slope timer has started counting up, the process also proceeds to step c10.

When it is determined in step c10 that the count value T _CP of the pole heart rate timer is equal to or longer than the set time T _RP, that is, the state in which the fluctuation range of the pole heart rate is extremely small continues for a long time, Next, in step c11, it is determined whether or not the count value T _CD of the extreme heart rate gradient timer is a preset time T _RD , for example, 30 seconds or more.

In step c11, it is determined that the count value T _CD of the pole heart rate gradient timer is equal to or longer than the set time T _RD , that is, the pole heart rate is rising or falling extremely gently for a long time. In that case, the awakening degree stable state experienced flag F _WS is set in the step c12, and then the 30-second average heart rate R _{A30 (n)} is adopted as the reference heart rate R _{HB in} the step c13. In step c14, the count value T _CP of the extreme heart rate timer and the count value T _CD of the extreme heart rate slope timer are reset to 0, and the steps after c1 are repeated based on the next interrupt signal.

In step c3, the absolute value of the value obtained by subtracting the 10-point moving average heart rate R _{A10 (n)} from the 30-second average heart rate R _{A30 (n)} exceeds 2, that is, the driver. It is judged that the fluctuation of the heart rate is relatively large, or in the step of c4, the current extreme heart rate R _{HP (n) is changed} to the previous extreme heart rate R.
It is judged that the absolute value of the value obtained by subtracting _{HP (n-1)} is 2 or more, that is, it is judged that the extreme heart rate R _HP fluctuates comparatively largely, or the slope of the extreme heart rate R _{HP in} the step c7. It is determined that the absolute value of D _RH is 1 or more, that is, the extreme point heart rate R _HP is rising or falling relatively suddenly, or the count value T _CP of the extreme point heart rate timer is set for the set time in step c10. T
_It is judged that _RP has not been reached, that is, the state where the fluctuation range of the pole heart rate is small has not continued for a long time, or the count value T _CD of the pole heart rate slope timer has reached the set time T _RD in the step of c11. If it is determined that the state in which the extreme heart rate does not rise or fall extremely slowly does not last for a long time, the process proceeds to step c15 and 3 is subtracted from the reference heart rate R _HB within the past 20 seconds. It is determined whether or not there is a pole heart rate R _{HP that} is equal to or more than the value and is equal to or less than the value obtained by subtracting 2 from the reference heart rate R _HB .

[0072] reference heartbeat rate R 3 values or more subtracted from _HB and reference heartbeat rate R peak point heartbeat rate that is less than or equal to the subtraction value from 2 _HB R _HP is present in the step of the c15 within the last 20 seconds, i.e. When it is determined that a conflict state due to a decrease in the driver's arousal level has occurred, the process moves to step c16 to set the conflict state experienced flag F _ST, and in step c17, the awake degree stable state experienced flag is set. It is determined whether _FWS is set. The reference heart rate 3 values or more subtracted from R _HB and reference heartbeat rate R peak point heartbeat rate following the subtracted value from 2 _HB R _HP does not exist within the past 20 seconds at step c15, namely When it is determined that the driver's arousal level does not cause a conflict, or when the reference heart rate R _HB is not set, the process proceeds to step c17, where the awakening level is set. If it is determined that the stable state experienced flag _FWS is not set, the process returns to step c1 based on the next interrupt signal. .

On the other hand, in the step c1, the conflict state
Tested flag F_STWhen it is determined that is set
Or, in the step of c17, the awakening degree stable state experienced flag
Gu F_WSIf it is determined that is set, c18
Alarm preparation flag F which will be described later in step_PRIs set
Is determined. Initially this alarm preparation flag
F_PRIs not set, move to step c19.
Go to reference heart rate R_HBTo current 4-point moving average heart rate R
_{A4 (n)}Whether or not the value obtained by subtracting more than 0 is less than or equal to 5
Judgment, and in this step c19, the reference heart rate R_HBFrom
Current 4-point moving average heart rate R_{A4 (n)}The value obtained by subtracting
Beyond 5 or less, that is, the driver's arousal level tends to decrease
If it is determined that there is an alarm, in step c20
Bi flag F _PRAfter setting the
Then, the steps after c1 are repeated.

If it is determined in step c18 that the alarm preparation flag F _PR is set, that is, if the driver's arousal level tends to decrease, the process proceeds to step c21, and this time the reference heart rate. It is determined whether or not the value obtained by subtracting the current heart rate R _{H (n)} from the number R _HB is smaller than 5, and this c21
Steps from the reference heart rate R _HB to the current heart rate R _{H ( n)}
When it is determined that the value obtained by subtracting is less than 5, that is, the degree of decrease in the heart rate is relatively small, the process proceeds to step c22, where the alarm level L _W is set to the first level, and the next interrupt Return to step c1 based on the signal. If it is determined in step c21 that the value obtained by subtracting the current heart rate R _{H (n)} from the reference heart rate R _HB is 5 or more, that is, the degree of decrease in the heart rate is relatively large, Go to step c19. Then, in this step c19, it is determined that the value obtained by subtracting the current 4-point moving average heart rate R _{A4 (n)} from the reference heart rate R _HB is larger than 5, that is, the driver's heart rate drop is considerably large. If it does, move to step c23 and move to the current extreme heart rate R
_It is determined whether or not the absolute value of the value obtained by subtracting the previous pole heart rate R _{HP (n-1 )} from _{HP (n)} is larger than 4.

[0075] The absolute value of a value obtained by subtracting the previous peak point heartbeat rate from the current peak point heartbeat rate _{R HP (n) R H P} (n-1) is determined in step c23 is greater than 4, i.e. the driver When it is determined that a large conflict state has occurred, it moves to step c24 and determines whether or not the adjacent pole heart rate timer starts counting up, and the adjacent pole heart rate timer counts. When it is determined that the up-point has not started, the count-up of the adjacent pole heart rate timer is started in step c25, and 1 is added to the adjacent pole heart rate data number N _DB in step c26. In step c27, it is determined whether the count value T _CB of the adjacent pole heart rate timer exceeds a preset time T _RB , for example, 20 seconds. When it is determined in step c24 that the adjacent pole heart rate timer has started counting up, the process proceeds to step c26.

In step c27, the adjacent pole heart rate is measured.
Timer count value T_CBIs the above set time T_RBBeyond
I.e. a large conflict with a relatively large change in heart rate
If it is determined that is continuing, step c28
To the count value T of the adjacent pole heart rate timer_CB0
It is reset to and at the step of c29, the adjacent pole center
Number of beats data N_DBAlso reset to 0, and then the c30 switch
Alarm level L at step_WWas set to the second level
Then, return to step c1 based on the next interrupt signal.
It In step c23, the current extreme heart rate R
_{HP (n)}To the previous extreme heart rate R_{HP (n-1)}Of the value obtained by subtracting
If the logarithmic value is 4 or less, that is, the conflict state occurs repeatedly
Even if it is determined that there is a warning, move to step c30
Report level L _WTo the second level.

Further, in the step c27, the adjacent pole points are
Heart rate timer count value T_CBIs the set time T_RBBelow
I.e. a large conflict with a relatively large change in heart rate
If it is determined that the
And the adjacent pole heart rate data number N_DBThan 3
It is judged whether the number is large or not, and the number N of heart rate data of the adjacent poles is determined. _DB
Is 3 or more, that is, because drowsiness occurs periodically
If it is determined that the conflict state is repeated, c3
Move to step 2 and alarm level L_WTo the third level
Set and step c1 based on the next interrupt signal
Return to. Also, in step c31 above, the adjacent pole heart rate
Number of data N_DBIs less than 3, that is, the conflict is repeated
If it is determined that there is not, go to step c30
It

By the way, when the vehicle attempts to travel accurately in accordance with the shape of the road, the driver steers the steering wheel 33 largely in accordance with the bend of the road on which the vehicle is traveling, and finely steers in accordance with the road surface condition. That is, when the driver travels on the road from the present position to the target position, the steering wheel 33 is largely steered along the road shape, and the driver travels on the road according to the road surface condition. At this time, the steering wheel 33 is used to finely control the position of the vehicle with respect to the instantaneous road. Then, by detecting the fine steering of the steering wheel 33, the awakening degree of the driver can be determined.

As shown in FIG. 23 showing the extracted enlarged sectional structure of the portion of the steering shaft 20 to which the steering angle sensor 21 is attached, the steering shaft 20 to which the steering handle 33 is integrally fixed is rotatable on the steering column 36. Is mounted on the steering shaft 20. A gear cylinder 37 is coaxially fitted to the steering shaft 20.
A drive gear 38 is formed integrally with the drive gear 7. Further, a steering angle sensor 21 which is a potentiometer is attached to the steering column 36 adjacent to the steering shaft 20, and a driven gear 40 is integrally attached to a rotary shaft 39 of the steering angle sensor 21. At the same time, the driven gear 40 is fitted with a backlash removing gear 41 capable of relative rotation. The driven gear 40 and the backlash removing gear 41 mesh with the drive gear 38 of the gear cylinder 37.

Therefore, when the steering handle 33 is operated, the steering shaft 20 is interlockedly rotated, and the driven gear 40 is rotated without play by the backlash removing gear 41 whose phase with the driven gear 40 is adjusted in advance. Then, the rotation accurately corresponding to the turning amount of the steering shaft 20 is transmitted to the rotating shaft 39 of the steering angle sensor 21, and the turning state of the steering shaft 20 is detected by the steering angle sensor 21 extremely accurately, and an electric signal is output. It can be output as.

The vehicle speed sensor 24 is of a type that detects the rotation of the output shaft of the transmission (not shown) in the present embodiment, but it is detected based on another known vehicle speed sensor, for example, the rotational speed of the driven wheels. Of course, it is also possible to adopt the one of the form.

The steering angle data processing means 22 calculates the standard value of the parameter of the steering component which is frequency-analyzed when the driver is awake, based on the detection signals from the steering angle sensor 21 and the vehicle speed sensor 24. The steering angle data is processed by applying a band pass filter composed of a calculation formula called a moving average based on the absolute value of the detection signal of the steering angle sensor 21. That is, the sampling frequency is 1
The steering angle data for every 0.1 second is sequentially taken in as 0 Hz. Then, this steering angle data is subjected to FFT analysis (FA
ST FOURIER TRANSFORM: Fast Fourier analysis) is performed to obtain the component magnitude (power spectrum) for each frequency band.

FIG. 24 is a graph showing the motion characteristics of the driver with respect to the frequency distribution of the steering angle signal of the steering wheel 33 obtained in this way, and the solid line shows running where the normal driver's awakening degree is high. What is shown in the broken line is when the driver's awakening level is lowered.
Also, in this graph, 1Hz means 1 in 1 second.
The steering wheel 33 is steered, while 0.1 Hz means steering the steering wheel 33 once every 10 seconds, and 0.5 Hz means steering the steering wheel 33 once every 2 seconds. That is. From this graph, it can be seen that if the driver's awakening degree is high, the number of times the steering wheel 33 is finely steered is increased, and if the awakening degree is low, the fine steering is reduced. Therefore, this steering wheel 3
It is considered that the driver's arousal level can be determined by detecting only the fine steering component region 3 and comparing it with a preset reference value.

That is, the detection data is divided into a predetermined frequency band by processing the detection data by calculating an average value of a plurality of points for each sampling period from the present to the past by a low-pass filter having a frequency equal to or lower than a predetermined frequency. it can. Specifically, from the graph shown in FIG. 24, the fine 0.3 to 1.0 Hz component of the steering wheel 33 is set as the visual steering component area S, and below 0.3 Hz, the steering wheel 33 is made larger along the road shape. Since it is a parameter indicating the steering amount to be steered, it is cut, and 1.0 Hz or more is also cut. The visual steering component will be described later.

Then, a moving average is calculated to divide this frequency band. Generally, the sample interval is I _s seconds,
When the cutoff frequency is f, the number M of samples to be averaged can be obtained by the following calculation formula. M = 0.443 / (I _S · f)

Therefore, in order to obtain the steering component area S _H of 1.0 Hz or less, the number of samples M _H when the cutoff frequency f is 1.0 Hz is calculated. Specimens when _{M H = 0.443 / (0.1 ×} · 1.0) = 4.43 Further, in order to obtain the following steering component area S _L 0.3 Hz, the cutoff frequency f is 0.3H _Z to calculate the number M _L of. M _L = 0.443 / (0.1 × · 0.3) = 14.8 Number of samples M for dividing the visual steering component region S in this way
It is calculated as _{H = 4, M L = 15} .

Therefore, sampling from the present to the past
4-point moving average steering angle P for each cycle_A4And 15-point moving average
Rudder angle P_A15And then these 1 and 7 seconds
Interval, that is, the sampling period is 0.1 seconds
, 4-point moving average steering angle P_A410-point moving average of
Below, this is called the 10 × 4 point moving average steering angle) P
_{A4-1 0}And 70-point moving average value (hereinafter, this is 70 × 4 points
This is called the moving average steering angle) P_A4-70And move 15 points
Uniform steering angle P_A1510-point moving average of
× 15 points called moving average steering angle) P_A15-10And 70
Point moving average value (hereinafter, this is 70 x 15 point moving average steering
We call it Kaku) P_A15-70And are calculated respectively. That
Then, by calculating the difference between them, in the visual steering component area S
Parameter P_S10, P _S70Can be calculated.

By the way, in the present embodiment, when a graph showing the driver's visual steering component with respect to the frequency distribution of the steering angle signal of the steering wheel 33 shown in FIG. A visual steering component of the driver during running (a graph indicated by a solid line) and a visual steering component of the driver during a drowsiness when the wakefulness is lowered (a graph indicated by a broken line) are obtained.

In general, the driver draws the traveling division zone of the road or himself by taking the traveling speed into consideration based on the visual information of "the shape of the road ahead" and "the position of the vehicle on the road at the present time". It is considered that the steering wheel 33 is operated so as to trace the target course. Therefore, the present inventor investigated how the visual limitation affects the operation characteristics of the steering wheel 33 by limiting a part of the visual information. That is, the steering wheel 33 is mainly subject to the "limitation of the visual information of the driver" and is influenced by "driving speed" and "individual difference".
The existence of visual steering and kinesthetic steering was confirmed from the effect on the operating angular frequency characteristics. This is already 7
The Mechanical Society of Japan “Dynamic and Design Conferenc”
e 1992 ”, and the outline of the test contents is explained below.

In a test study on the operation characteristics of the steering wheel 33 by the driver, the vehicle traveled at a predetermined traveling speed on a predetermined curved road, and at this time, a part of the driver's glasses was masked to limit the visibility. . That is, as shown in FIG. 26, a traveling test was performed with the field of view ahead of the vehicle 42 being limited by a predetermined distance, and the steering angle data of the steering wheel 33 at this time was subjected to frequency analysis to examine its characteristics. As a result, when the frequency is analyzed between the case where the driver normally travels and the case where the upper field of view is restricted, as shown in FIG. 25, as shown in FIG. 25, there is a significant difference between the two at 0.3 to 1.0 Hz. Appeared. What can be estimated from this analysis result is 0.3-1.0.
The data in the Hz region is a fine feedback correction steering that controls the positional relationship between the vehicle 42 and the road in front of the vehicle 42 based on the visual information in the operation of the steering wheel 33, that is, the visual steering component. is there. In this test, since the upper field of view was limited, it can be said that the visual steering component was more prominent than during normal driving.

Therefore, the steering angle data of the steering wheel 33 is frequency-analyzed, and the data in the range of 0.3 to 1.0 Hz is extracted from the obtained result to obtain a fine steering component of the steering wheel 33, that is, a visual steering component. Can be detected
In addition, the fact that the trends in the graph shown in FIG. 25 match also makes it possible to determine the awakening degree of the driver based on the data of the visual steering component region.

27 and 28 show the processing flow in the steering angle data processing means 22 in this embodiment. That is, the steering angle data processing means 2 in this embodiment.
The process of No. 2 is performed every predetermined period, for example, every 15 ms interrupt signal. First, at the sampling period of 0.1 sec in step d1, the steering angle θ from the steering angle sensor 21 and the vehicle speed. The vehicle speed V from the sensor 24 is read. Then, it is determined in step d2 whether or not the read absolute value of the steering angle θ is less than 10 °, and when it is determined that the absolute value of the steering angle θ is less than 10 °, the step d3 is performed. However, if it is determined that the absolute value of the steering angle θ is 10 ° or more, the process proceeds to step d4, and after resetting the number N _S of effective steering angle data up to now to 0, d1 is again set.
Return to step. When the steering angle θ travels at 10 ° or more, the driver is operating the steering wheel 33 largely, and at this time, the visual steering component necessary for determining the awakening degree of the driver is obtained. Is not appropriate as data for

Vehicle speed V read in step d3
Is 30 km / h or more, and the vehicle speed V is 30 km
If it is determined that the vehicle speed V is less than or equal to / h, the process proceeds to step d5, but if the vehicle speed V is determined to be less than 30 km / h, the process proceeds to step d4. Back again to d1 of the step the N _S is reset to 0. When traveling at a vehicle speed V of less than 30 km / h, for example, when traveling at a low speed on a congested road,
At this time, the driver may operate the meaningless steering wheel 33, and thus data that is not appropriate for determining the driver's arousal level may be taken in. Therefore, as described above, the absolute value of the steering angle θ is 10
D4 when the vehicle speed V is less than 30km / h
The steering angle θ read in the step is not adopted.

In step d5, the number N _S of effective steering angle data adopted in steps d2 and d3 is incremented by one. Then, in step d6, it is determined whether or not the number N _{S of} effective steering angle data is four or more. If it is determined that there are four or more, the process proceeds to step d7. Then, in step d7, the four-point moving average steering angle P _A4 is calculated, the process proceeds to step d8, and the four-point moving average steering angle data of the four-point moving average steering angle P _A4 calculated in step d7 is calculated. _{Raise the} number N _P4 by one. When it is determined in step d6 that the number N _{S of} effective steering angle data is not four or more, in step d7 the four-point moving average steering angle P _A4
Cannot be calculated, the process returns to step d1 again.

In step d9 following step d8, it is determined whether the number N _{S of} effective steering angle data is 15 or more. If it is determined that this is 15 or more, the process proceeds to step d10. Then, the 15-point moving average steering angle P _A15 is calculated in step d10, and the process shifts in step d11 to increment the 15-point moving average steering angle data number N _P15 by one. If it is determined in step d9 that the number of 15-point moving average steering angle data N _S is 15 or more, in step d10 the 15-point moving average steering angle P is calculated.
_Since the calculation process of _A15 cannot be performed, the process returns to step d1 again.

In step d12, it is determined whether or not the four-point moving average steering angle data number N _P4 is 10 or more. The four-point moving average steering angle P _A4-10 is calculated, and the _{process proceeds} to step d14. And this d1
In step 4, the number of 15-point moving average steering angle data is N _{P1 5}
Is determined to be 10 or more, and if it is determined to be 10 or more, the process _proceeds to step d15 to calculate the above-mentioned 10 × 15-point moving average steering angle P _A15-10 , and d16
Go to step. When it is determined that the number of 4-point moving average steering angle data N _P4 or the number of 15-point moving average steering angle data N _P15 is 10 or more in steps d12 and d14, 10 × in steps d13 and d15. Four
Since the point moving average steering angle P _A4-10 and the 10 × 15 point moving average steering angle P _A15-10 cannot be calculated, the process returns to step d1.

At the step d16, it is judged whether or not the four-point moving average steering angle data number N _P4 is 70 or more. The four-point moving average steering angle P _A4-70 is calculated, and the process proceeds to step d18. Then, in step d18, the 15-point moving average steering angle data number N _P15 is 7
It is determined whether or not there is 0 or more, and when it is determined that there is 70 or more, the process proceeds to step d19 and the above-mentioned 70 × 15.
The point moving average steering angle P _A15-70 is calculated. In addition, in steps d16 and d18, the 4-point moving average steering angle data number N
If it is determined that the number of data points _P4 or 15-point moving average steering angle data N _P15 is not 70 or more, d17 and d19
Since the calculation processing of the 70 × 4 point moving average steering angle P _A4-70 and the 70 × 15 point moving average steering angle P _A15-70 cannot be performed in the step, the process returns to step d1 again.

The steering wakefulness determining means 23 is a reference value of steering component parameters (hereinafter,
This is referred to as a reference parameter), and the current awakening degree of the driver is determined, and an alarm level corresponding to this awakening degree is set. That is, the 10 × 4 moving average steering angle P calculated by the steering angle data processing means 22.
_A4-10 and _70x4 moving average steering angle P _A4-70 and 10x
From the 15-point moving average steering angle P _A15-10 and 70 × 15-point moving average steering angle P _A15-70 , the parameters P _S10 and P _S70 of the visual steering component area S are calculated based on the following formulas, respectively. To do. P _S10 = | P _A4-10 -P _A15-10 | P _S70 = | P _A4-70 -P _A15-70 | And the parameters P _S10 , P of this visual steering component region S
The degree of awakening degree of the driver is determined by comparing _S70 with a preset reference parameter.

The steering wakefulness judgment in the present embodiment as described above
29 and 30 show the flow of processing in the setting means 23.
You That is, the steering alertness determination means 23 in the present embodiment is
The processing is performed in a predetermined cycle, for example, an interrupt signal every 15 milliseconds.
First, 70x4 points in step e1
Moving average steering angle P_A4-70And 70 × 15 points moving average steering
Corner P_A15-70Based on the absolute value of the difference between
Parameter P_S70To calculate. Then, in the step of e2
The parameter P of the visual steering component area S calculated by _S70Based on
Quasi-parameter P_SS70It is judged whether or not the above
Parameter P of rudder component area S_S70Is the reference parameter P_SS70
When it is determined that it is less than, move to step e3
It

In this step of e3, 10 × 4 point moving average steering angle P _A4-10 and 10 × 15 point moving average steering angle P
The parameter P _{S1 0} of the visual steering component area S is calculated from the absolute value of the difference from _A15-10 . Then, whether the parameter P _S10 of the visual steering component area S is the reference parameter P _SS10 less determined at step e4, the parameter P _S10 of the visual steering component area S is a reference parameter P _SS10 less If it is determined, the process proceeds to step e5.

This reference parameter is set according to the degree of awakening of the driver, and in this embodiment, 0.21 is set as the reference parameter P _{S S70} corresponding to the visual steering component parameter P _S70. Then, as the reference parameter P _SS10 corresponding to the visual steering component parameter P _S10 , 0.1
7 is set. Then, the calculated parameters P _S10 and P _S70 of the visual steering component region S are set to the reference parameter P _S10 .
Alarm level L _W corresponding to arousal level compared to _SS70 and P _SS10
To set. These reference parameters P _SS70 , P
_SS10 is set on the basis of the graph shown in FIG. 24 showing the visual steering components of the traveling time when the awakening degree of the driver is lowered with respect to the frequency distribution and the traveling time when the awakening degree is high as described above. Therefore, these numerical values are not limited to the values in the above-described embodiment, and may be set appropriately based on various conditions.

The parameter P _{S70 of} the visual steering component area S calculated in step e2 is the reference parameter P.
When it is determined that it is larger than _{SS70, the process proceeds} to step e6, and when it is determined that the parameter P _{S10 of} the visual steering component region S calculated in step e4 is larger than the reference parameter P _SS10. Moves to step e6. In this step of e6, the count value T _CU of the awakening degree lowering timer is reset to 0 because it is determined that the driver's awakening degree is high, and the steps after e1 are repeated again based on the next interrupt signal.

In step e5, it is determined whether or not the awakening degree reduction timer has started counting up. If it is determined that this has not started counting up, in step e7, the awakening degree reduction timer is determined. Starts counting up, and in step e8, the count value T _CU of the awakening degree lowering timer is a preset time T _RU , for example, 3
Whether or not less than a second, that is, P _S70 ≧ P _SS70 and P _S10 ≦
It is determined whether or not the state of P _SS10 continues for the set time T _RU or more, and if it is determined that it is the set time T _RU or less, the process moves to step e6 described above and the awakening timer counts down. Although the value T _CU is reset to 0, if it is determined that the value is not 0, the process proceeds to step e9.

At the step e9, it is judged whether or not the alarm switching timer has started counting up, and if it is judged that this has not started counting up,
In step e10, the count-up of the alarm switching timer is started, and in step e11, the count value T _CW of the alarm switching timer is set to the reference alarm switching time T _BW set in advance to the first addition time T _AL , For example, it is determined whether it is longer than the time obtained by adding 4 seconds. When it is determined that the count value T _CW of the alarm switching timer is longer than the sum of the reference alarm switching time T _BW and the first addition time T _AL , that is, it is determined that the driver's arousal level is the lowest. Shifts to step e12 and sets the alarm level L _W to the third level, and then shifts to step e17 described later.

When it is determined in step e11 that the count value T _CW of the alarm switching timer is not longer than the sum of the reference alarm switching time T _BW and the first addition time T _AL , e13 Then, it is determined whether or not the count value T _CW of the alarm switching timer is longer than the second addition time T _AS set in advance to the reference alarm switching time T _BW , for example, 3 seconds. If it is determined that the count value T _CW of the alarm switching timer is longer than the sum of the reference alarm switching time T _BW and the second addition time T _AS , the process proceeds to step e14 to output the alarm level L. Set _W to second level.

Further, when it is determined in step e13 that the count value T _CW of the alarm switching timer is not longer than the sum of the reference alarm switching time T _BW and the second addition time T _AS , the value of e15 is determined. In Step S, it is determined whether or not the count value T _CW of the alarm switching timer is longer than the reference alarm switching time T _BW . Then, the count value T of this alarm switching timer
If it is determined that _CW is longer than the reference alarm switching time T _BW , the process proceeds to step e16 to set the alarm level L _W to the first level.
After setting the level, the process proceeds to step e17 described later.

If it is determined in step e14 that the count value T _CW of the alarm switching timer is equal to or shorter than the reference alarm switching time T _BW , the process proceeds to step e17, in which the count value T _CU of the wakefulness lowering timer is reached. After resetting the count value T _CW of the alarm switching timer to 0, the steps after e1 are repeated based on the next interrupt signal.

The tactile alarm means 26 allows the pair of left and right side supports 44 provided on the seat back 43 of the driver's seat 25 to rotate in the direction of the arrow in FIG. Tighten from both sides,
On the contrary, the operation of pulling the side support 44 away from the flank is repeated to prompt the driver to improve the arousal level by the sense of touch, and when the driver's grip on the steering wheel 33 is not correct, First mentioned above
It operates in response to the alarm level L _W of the level.

Further, the visual alarm means 28 has a display 45 embedded in the front window 27 in front of the driver's seat 25 for transparently displaying the drowsiness alarm, which is transparent in a non-energized state and obstructs the view. In the energized state without occurrence, for example, the doze warning mark 46 as shown in FIG. 2 blinks in a transparent state to visually prompt the driver to improve the arousal level. The alarm level L _W is set to operate.

Further, the audible alarm means 29 is adapted to audibly prompt the driver to improve the arousal level by sounding an alarm buzzer 48 incorporated in the instrument panel 47. If the driver's grip on 33 is not correct, or if the third level warning level L _W described above is activated.

The defective handle grip warning means 34 in the present embodiment is the two warning means 2 as described above.
We are trying to use 6,29. Side support 4
By changing the movement of No. 4 and the sounding of the alarm buzzer 48 from those for improving the arousal level, whether the driver easily grips the steering wheel 33 or whether it is an alarm for drowsy driving can be determined. Consideration is given so that they can be distinguished.

The alarm control means 30 activates the above-mentioned three alarm means 26, 28, 29 based on the alarm levels L _W determined by the heartbeat awakening degree determination means 19 and the steering awakening degree determination means 23, respectively. When the signal of the ON operation of the alarm release switch 31 by the driver is input, the three alarm means 26, 2 based on the alarm level L _W are controlled.
The operation of 8,29 is stopped. But,
Warning means 26, 2 as the handle grip failure warning means 34
When 9 is operated, these operations are not stopped even if the driver turns on the alarm release switch 31.

The flow of alarm processing by the alarm control means 30 is shown in FIGS. 31 and 32. That is, the alarm process in the present embodiment is performed every predetermined period, for example, every 15 msec interrupt signal. First, in step f1, it is determined whether the alarm level L _W is the first level, When it is determined that the alarm level L _W is the first level, the process proceeds to step f2 and it is determined whether the alarm generation flag F _WG is set. When the step in warning generation flag F _WG of the f2 has been determined not to be set starts counting up of the warning change-over timer with setting the warning generation flag F _WG at f3 step, f4 In the step of, the count value T _CW of the alarm switching timer is the first preset time T _WL , for example, 1
It is determined whether it exceeds 0 seconds.

When it is determined in step f4 that the count value T _CW of the alarm switching timer is less than or equal to the first set time T _WL , the process moves to step f5 to activate the tactile alarm means 26. , The side support 44 is pulled away from or pressed against the driver's flank to prompt the driver to wake up by tactile sensation, and then f is determined based on the next interrupt signal.
Return to step 1.

If it is determined in step f2 that the alarm generation flag _FWG has been set, then f4
Shift to the step of and the count value of the alarm switching timer T _CW
Determines again whether or not the time exceeds the first set time T _WL .

Further, in this step of f4, the count value T _CW of the alarm switching timer exceeds the first set time T _WL , that is, the wakefulness of the driver cannot be returned only by operating the tactile alarm means 26. If it is determined, the process proceeds to step f6 to set the alarm level L _W to 2 levels, and then f7
In step f8, the alarm generation flag F _WG is reset, and in step f8, the count value T _{CW of the} alarm switching timer is reset.
After resetting 0 to 0, the visual warning means 28 is activated in the step of f9, the warning mark 46 is displayed on the front window 27, and after visually awakening the driver,
Return to step f1 based on the next interrupt signal.

When it is determined in step f1 that the alarm level L _W is not the first level, the process proceeds to step f10 to determine whether the alarm level L _W is the second level. If it is determined in step f10 that the alarm level L _W is the second level, f
Warning generation flag F _WG proceeds to step 11 to determine whether it is set, when the warning generation flag F _WG is determined in step f11 is determined not to be set, in step f12 Then, the alarm generation flag F _WG is set and the count-up of the alarm switching timer is started, and it is determined in step f13 whether the count value T _CW of the alarm switching timer exceeds the first set time T _WL. To do.

When it is determined in step f13 that the count value T _CW of the alarm switching timer is only the first set time T _WL or less, the process shifts to step f9 to activate the visual alarm means 28. Then, the warning mark 46 is displayed on the front window 27 to prompt the driver to awaken. In addition,
If it is determined in step f11 that the alarm generation flag F _WG is set, the process proceeds to step f13 to determine whether the count value T _CW of the alarm switching timer exceeds the first set time T _WL . Determine again whether or not.

In step f13, the count value T _CW of the alarm switching timer exceeds the first set time T _WL ,
That is, when it is determined that the driver's arousal level does not return by the operation of the visual warning means 28, the process shifts to step f14, the alarm level L _W is set to the third level, and the alarm is issued in step f15. The flag F _WG is reset and at the step f16, the count value T _{CW of the} alarm switching timer
After resetting 0 to 0, the auditory warning means 29 is activated in step f17, and the alarm buzzer 48 is sounded to prompt the driver to wake up by hearing, and then the process returns to step f1 based on the next interrupt signal. .

At step f10, the alarm level L _W
If it is determined that the warning level L _W is not the second level, the process proceeds to step f18, and it is determined whether the warning level L _W is the third level.
_When it is determined that _W is at the third level, the process proceeds to step f19, and it is determined whether the alarm generation flag _FWG is set. When it is determined that the warning generation flag F _WG is determined in step f19 is set actuates the auditory warning means 29 proceeds to step of the f17, driver blew a warning buzzer 48 Promotes awakening. If it is determined that the alarm generation flag F _WG is not set at step f19, the process proceeds to step f20 to set the alarm generation flag F _WG and at step f21 the alarm switching timer is set. After starting the count up of, the process proceeds to step f17.

On the other hand, the process goes to step f18 to issue an alarm
Bell L_WF is not the third level, f
Move to step 22 and go to Conflict status flag F_ST
Is set, and this conflict state experience
Finished flag F_STWhen it is determined that is set
Is the three alarm means 26, 28, 2 in the step of f23.
All the operations of 9 are stopped, and further in step f24
Wisteria state experienced flag F _STTo reset. Also, the above f
Move to step 22 and go to Conflict status flag F_ST
If it is determined that is not set,
The process returns to the step of f1 based on the interrupt signal of.

The handle grip failure alarm processing unit 35 incorporated in the alarm control means 30 includes the heartbeat processing means 13, 1.
Based on the information of the input normality determination flag F _NI set in the process of the arithmetic processing in 4, 17, the degree of grip of the steering wheel 33 by the driver is estimated, and the operation of the above-mentioned steering wheel grip failure warning means 34 is controlled. If the state in which the input normality determination flag F _NI is not set continues for a certain period of time, the tactile alarm means 26 is first activated to call the driver's attention. The alarm means 29 is further activated.

FIG. 33 shows the flow of processing based on the information from the heartbeat processing means 17 in the steering wheel grip failure warning processing section 35 of this embodiment. That is, the processing of the handle grip failure warning processing unit 35 in this embodiment is performed in a predetermined cycle,
For example, it is performed every 15 ms interrupt signal,
First, determine whether the set of input normal determination flag F _NI performed in heartbeat processing means 13, 14, and 17 is performed in step g1, the input normal determination flag F _NI is not set, That is, when it is determined that the driver's grip on the steering wheel 33 may not be correct, the process proceeds to step g2 to determine whether the count value T _CI of the input failure integration timer is equal to or longer than the set time T _RI . To judge.

If it is determined in step g2 that the count value T _CI of the input failure integration timer is equal to or longer than the set time T _RI , the handle grip failure warning preparation timer starts counting up in step g3. If it is determined that the handle grip failure warning preparation timer has not started counting up,
In step g4, the handle gripping failure alarm preparation timer starts counting up, and in step g5, the count value T _{CS of the} steering wheel gripping failure preparation timer exceeds a preset time T _RS , for example, 2 seconds. Determine whether or not. If it is determined in step g3 that the count of the steering wheel grip failure alarm preparation timer has started, the process proceeds to step g5 and the count value T _{CS of the} steering wheel grip failure alarm preparation timer is set to the above value. Time T
Determine if _RS is exceeded.

Go to step g5 and hold the handle.
Failure alarm preparation timer count value T_CSIs the set time T_RS
If it is judged that the value exceeds the limit, move to step g6.
The handle grip failure alarm switching timer to count up.
The handle is gripped.
The failure alarm switching timer has not started counting up.
If it is determined that the answer is yes, move to step g7 and
Start counting up the dollar gripping alarm switching timer
Then, at the step of g8, the handle tie alarm switching tie
Ma count value T_CHIs a preset time T_RH, For example
It is determined whether it exceeds 3 seconds. Also, the step of g6
And the handle gripping failure alarm switching timer counts.
If it is determined that the start-up has started, this g8
Move to the step of and handle failure alarm switching timer
Count value T_CHIs the above set time T _RHWhether or not
To determine.

Then, at the step of g8, the handle is gripped.
Fault alarm switching timer count value T _CHIs the set time T_RHSince
Down, i.e. not holding the steering wheel 33 correctly
If it is determined that the state duration is short, g9
Up to activate the tactile warning means 26,
Separate or push the side support 44 against the flank
To prevent the driver from gripping the steering wheel 33 correctly.
To alert the user with tactile attention and then based on the next interrupt signal.
Then return to step g1.

Also, in the step g8, the handle is gripped.
Fault alarm switching timer count value T _CHIs the set time T_RHTo
Exceeding, that is, driving only by operating the tactile alarm means 26
If it is determined that the person's attention cannot be called, g10
Shift to the step, further activate the auditory warning means 28,
The side support 44 is pulled away from the driver's flank
The alarm buzzer and
The tactile sense and hearing so that the transfer person can grasp the steering wheel 33 correctly
Based on the next interrupt signal after alerting
Return to step g1.

In step g5, the count value T _{CS of the} steering wheel grip failure warning preparation timer is set to the set time T _RS.
When it is determined that the following is true, the process directly returns to the step g1 based on the next interrupt signal. Further, when the input normality determination flag F _NI is set in the step g1, that is, when the driver determines that the steering wheel 33 is correctly gripped, or in the step g2, the count value of the input failure integrating timer. When it is determined that T _CI is less than the set time T _RI , the process proceeds to step g13 to reset the count value T _CS of the steering wheel grip failure alarm preparation timer to 0 and activate the steering wheel grip failure alarm means 34. After stopping, it returns to the step of g1 based on the next interrupt signal.

33, the processing flow of the handle grip failure warning processing section 35 based on the information from the heartbeat processing means 17 corresponding to the potential type heartbeat sensor 16 has been described, but it corresponds to the infrared type heartbeat sensors 11 and 12. It goes without saying that the similar alarm processing is performed by the handle grip failure alarm processing unit 35 based on the information from the heartbeat processing means 13 and 14.

The reference value correction unit 32 includes the alarm means 26,
After 28 and 29 are activated, the driver releases the alarm release switch 3
Based on the time until 1 is operated, if this time is short, it is determined that the driver's arousal level is relatively high, and the warning means 2
The reference heart rate R _HB and the reference alarm switching time T _BW are corrected to a higher value so that 6, 28, 29 become harder to operate, while the driver gives an alarm after the alarm means 26, 28, 29 are activated. If it takes a long time to operate the release switch 31, it is determined that the driver's arousal level is lower than expected, so that the alarm means 26, 28, 29 are activated relatively early. Reference heart rate R _HB and reference alarm switching time T _BW
Of the reference heart rate R _HB corrected in this way
And the reference alarm switching time T _BW are output to the heartbeat / wakefulness determination means 19 and the steering / wakefulness determination means 23, respectively.

FIG. 34 shows the flow of processing in the reference value correction unit 32 in this embodiment. That is, the process of the reference value correction unit 32 in the present embodiment is started by turning on the alarm release switch 31, but first, the alarm release flag F _ST is set at step h1, and then the alarm is issued at step h2. It is determined whether the count value T _CW of the switching timer exceeds the second preset time T _WM , for example, 6 seconds.

At this step h2, the alarm switching timer
Count value T_CWIs the second set time T_WMBeyond
That is, if the driver's reaction is not too fast
Moves to the step of h3 and this warning is the steering awakening degree
It is determined whether the alarm is based on the information from the determination means 23,
This warning is based on the information from the steering alertness determination means 23.
If it is judged as an alarm, move to step h4
And the standard alarm switching time T _BWAnd set it to 1 second less,
Make sure that the reporting means 26, 28, 29 work slower than before.
It Furthermore, at the step of h5, the alarm switching timer is counted.
Value T_CWAfter resetting to 0, based on the next interrupt signal
Then, the process returns to step h1. Also, the above step h3
At this time, the warning is based on the information from the steering alertness determination means 23.
It is not based on the alarm, that is, from the heartbeat / wakefulness determination means 19.
If it is determined that the alarm is based on the information
Go to step and reference heart rate R_HBSet one less
Fix, alarm means 26, 28, 29 actuate slower than before
Then, in step h5, the alarm switching timer
Count value T_CWIs reset to 0.

On the other hand, when it is determined in step h2 that the count value T _CW of the alarm switching timer is less than or equal to the second set time T _WM , the process proceeds to step h7 and this time the alarm switching timer starts. the count value T _CW is the third preset time T _WS, for example, to determine shorter or not than 2 seconds, the count value T _CW is less than the third set time T _WS, i.e. the driver of the reaction very If it is determined that the warning is early, the process proceeds to step h8, and it is determined whether or not the present alarm is an alarm based on the information from the steering alertness determination means 23. Then, at this step h8, the current warning is the steering wakefulness determination means 2
When it is judged that the alarm is based on the information from 3,
After shifting to the step of h9, the reference alarm switching time T _BW is set again by one second longer so that the alarm means 26, 28 and 29 are actuated later than before, and then the step of h5 is further advanced. Further, if it is determined in step h8 that the current alarm is not an alarm based on the information from the steering awakening degree determining means 23, that is, an alarm based on the information from the heartbeat awakening degree determining means 19, the step in h10 is performed. , The reference heart rate R _HB is increased by one, and the alarm means 26, 28, 2 is set.
After making 9 operate later, the process moves to the step of h5.

When it is determined in step h7 that the count value T _CW of the alarm switching timer is equal to or greater than the third set time T _WS , the current reference heart rate R _HB and reference alarm switching time T W are set. Without changing _BW , the process shifts to step h5 to reset the count value T _CW of the alarm switching timer to zero.

[0135]

As described above in detail with reference to the embodiments, according to the heart rate detecting apparatus of the present invention, the heart rate detecting device has a light projecting section for projecting infrared rays and a light receiving section for receiving infrared rays to prevent pulsation of blood. An infrared heart rate sensor for detecting the heart rate of the driver and at least two electrodes A potential heart rate sensor for detecting the heart rate of the driver from the potential difference due to the pulsation between both hands and time series data by the infrared heart rate sensor The heart rate data processing means adopts the larger value as the effective heart rate by comparing the number of heartbeats with the time series data of the heart rate by the potential type heart rate sensor. Even if it is not possible, the heart rate can be detected by the other heart rate sensor, and the heart rate of the driver can be reliably and accurately detected by preventing detection failure of the heart rate.

According to the heart rate detecting device of the present invention,
When the driver grips the steering wheel at a position where the driver frequently grips the steering wheel, a heartbeat sensor having an infrared light emitting portion and an infrared light receiving portion is provided at the contact position of the portion with a large blood flow of the hand and the heartbeat Since the elastic member is provided around the position where the sensor is arranged and formed to have a predetermined curvature in accordance with the shape of the contacting hand part, the elastic member absorbs the variation of the pressing force of the fingertip and disturbs the blood flow under the skin. This can be prevented, and the driver's hand is closely attached to the heart rate sensor so that it is less likely to be affected by outside light, and the heart rate of the driver can be accurately detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic structure of an embodiment of a vehicle dozing warning device according to the present invention.

FIG. 2 is a perspective view showing an external appearance of a vehicle compartment in this embodiment.

FIG. 3 is a graph showing changes over time in driver's arousal level.

FIG. 4 is a front view of a steering handle.

FIG. 5 is a side view of a steering handle.

FIG. 6 is a sectional view of an infrared heartbeat sensor.

FIG. 7 is a sectional view of a wheel of a steering wheel.

FIG. 8 is a schematic diagram of a steering handle representing another infrared heartbeat sensor and a potential type heartbeat sensor.

9 is a sectional view taken along line IX-IX in FIG.

10 is a sectional view taken along line XX of FIG.

FIG. 11 is a schematic diagram showing a state in which a steering handle is gripped by a hand.

FIG. 12 is a schematic diagram of a steering wheel representing another infrared heart rate sensor.

FIG. 13 is an explanatory diagram showing a portion of a hand having a large blood flow.

FIG. 14 is a front view of a steering wheel representing another potential type heartbeat sensor.

FIG. 15 is a conceptual diagram showing a relationship between a heartbeat pulse from a heartbeat sensor and heartbeat rate data calculated by a heartbeat processing means.

16 is a flowchart showing the flow of processing by the heartbeat processing means of the present embodiment together with FIG. 17 and FIG.

FIG. 17 is a flowchart showing the flow of processing by the heartbeat processing means of the present embodiment together with FIG. 16 and FIG.

FIG. 18 is a flow chart showing the flow of processing by the heartbeat processing means of the present embodiment together with FIG. 16 and FIG.

FIG. 19 is a flowchart showing the flow of processing by the heartbeat data processing means of the present embodiment.

FIG. 20 is a flow chart showing the flow of processing by the heartbeat / wakefulness determination means of the present embodiment together with FIG. 21 and FIG. 22.

FIG. 21 is a flow chart showing the flow of processing by the heartbeat / wakefulness determination means of the present embodiment together with FIG. 20 and FIG. 22.

22 is a flowchart showing the flow of processing by the heartbeat / wakefulness determination means of the present embodiment together with FIG. 20 and FIG. 21.

FIG. 23 is an extracted enlarged sectional view of a portion of a steering shaft to which a steering angle sensor is attached.

FIG. 24 is a graph showing the visual steering component of the driver with respect to the frequency distribution of the steering angle of the steering wheel.

FIG. 25 is a graph showing the frequency distribution of the steering angle of the steering wheel when the driver's upper field of view is restricted.

FIG. 26 is a schematic diagram showing an upper view restriction area of a vehicle driver.

FIG. 27 is a flowchart showing the processing flow by the steering angle data processing means of the present embodiment together with FIG. 28.

28 is a flowchart showing the flow of processing by the steering angle data processing means of the present embodiment together with FIG. 27.

FIG. 29 is a flowchart showing the processing flow by the steering alertness determination means of this embodiment together with FIG. 30.

30 is a flowchart showing the flow of processing by the steering alertness determination means of the present embodiment together with FIG. 29.

FIG. 31 is a flowchart showing the flow of alarm processing by the alarm control means of the present embodiment together with FIG. 32.

32 is a flowchart showing the flow of alarm processing by the alarm control means of the present embodiment together with FIG. 31.

FIG. 33 is a flowchart showing a flow of processing by a handle grip failure warning processing unit of the present embodiment.

FIG. 34 is a flowchart showing the flow of processing by the reference value correction unit of the present embodiment.

[Explanation of symbols]

 11, 12 are infrared type heart rate sensors, 13, 14 and 17 are hearts
Beat processing means, 15 signal selection means, 16 and 81 potential type
Heart rate sensor, 16a, 16b electrodes, 18 heart rate data
Processing means, 19 is heartbeat / wakefulness determination means, 20 is a steering axis,
Reference numeral 21 denotes a steering angle sensor, 22 a steering angle data processing means, 2
3 is steering wakefulness determination means, 24 is a vehicle speed sensor, and 25 is operation
Transfer seat, 26 is alarm means, 27 is front window, 2
8 and 29 are alarm means, 30 is alarm control means, and 31 is an alarm
Release switch, 32 is a reference value correction unit, 33 is a steering hand
34, 34 is a handle grip failure warning means, and 35 is a handle
Poor grip warning processing unit, 36 is a steering column, 37 is a gear
A cylinder, 38 a drive gear, 39 a rotary shaft, 40 a driven gear,
41 is a gear for removing backlash, 42 is a vehicle, 43 is
Seat back, 44 is side support, 45 is display
Ray, 46 is a doze warning mark, 47 is instrument
Front panel, 48 is an alarm buzzer, 51 is a hub, and 52 is a ho
Eel, 53 is rim, 53 is urethane foam, 61 is light emission
Part (infrared light emitting diode), 62 is a light receiving part (photo
Transistor, 63 is a housing, 67 and 68 are electrodes,
69 is a controller, 70 is a blood vessel, 71 is a cover 71,
72 is an elastic member. Also, D_RHIs the adjacent pole heart rate
Between, F_NIIs a normal input determination flag, F_PRIs an alarm
Bi flag, F_RIs the heart rate data hold flag, F_STIs a conflict
State experienced flag, F_U1Is the first input failure determination flag,
F_U2Is the second input failure determination flag, F_WGIs the alarm generation flag
Gu, F_WSIs the awakening degree stable state experienced flag, f is the cutoff period
Wave number, I_MNIs the minimum pulse interval, I_MXIs the maximum pulse interval,
I_PIs the pulse interval, I_PBIs the reference pulse interval, I_SIs between samples
Distance, L_WIs the alarm level, M is the number of samples to be averaged, M_AI
Is the pole index of the 4-point moving average heart rate, M_HIs the number of samples, M_L
Is the number of samples, M_PIIs the pole index of the pole heart rate, N_DIs heartbeat
Number of data, N_DAIs the number of effective heart rate data, N_DBIs the adjacent pole
Number of point heart rate data, N_DEIs the heartbeat by the potential heartbeat sensor
Number of data, N_DIIs the heart rate
Number of data, N_P4Is the 4-point moving average steering angle data number, N_P15Is
15-point moving average steering angle data number, N_SIs the effective steering angle day
Number, P_A4Is a four-point moving average steering angle, P_A4-10Is 10 × 4
Point moving average steering angle, P_A4-70Is 70 x 4 point moving average steering
Corner, P_{A15 (n)}Is a 15-point moving average steering angle, P_A15-10Is 10
× 15 points moving average steering angle, P_A15-70Moves 70 × 15 points
Average steering angle, P_S10Is the parameter of the visual steering component range, P
_S70Is the parameter of the visual steering component range, P_SS10Is the reference para
Meter, P_SS70Also the reference parameter, R_A4Is a 4-point moving average
Heart rate, R_A10Is a 10-point moving average heart rate, R_A30Is 30 seconds
Average heart rate, R_HIs the heart rate, R_HBIs the reference heart rate, R_HPIs
Pole heart rate, S is the visual steering component range, S_HIs the visual steering component
Area, S_LIs the visual steering component range, T_AIs the addition time, T_ALIs first
Time of addition, T_ASIs the second addition time, T_BWIs the standard alarm off
Exchange time, T_CBIs the count value of the adjacent pole heart rate timer, T
_CDIs the count value of the pole heart rate slope timer, T_CHIs a hand
Le gripping alarm switching timer count value, T_CIIs a bad input product
Count value of arithmetic timer, T_CPIs the cow of the extreme heart rate timer
Value, T _CRIs the count value of the heart rate data timer, T_CS
Is the count value of the handle grip failure alarm preparation timer, T_CW
Is the count value of the alarm switching timer, T_CUAwakened Thailand
Ma's count value, T_HLIs the standard alarm preparation time, T_RBIs adjacent
Pole heart rate timer setting time, T_RDIs the polar heart rate slope
Imama's set time, T_RHIs the handle grip alarm switching timer
Set time, T_RIIs the set time of the input failure integration timer, T_RP
Is the setting time of the extreme heart rate timer, T_RSIs the handle grip
Good alarm preparation timer setting time, T_RUIs the awakening timer
Setting time of T_SIs the subtraction time, T_WLIs the alarm generation timer
First set time, T_WMIs the second setting of the alarm generation timer
While T_WSIs the third set time of the alarm generation timer, t_PIs the heart
The pulse pulse detection time, V is the vehicle speed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidemitsu Sato 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Yasushi Sekine 5-33-8, Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation

Claims (2)

[Claims] 1. An infrared heart rate sensor for detecting a driver's heart rate from blood pulsation, the infrared heart rate sensor having a light projecting unit provided on a steering wheel for projecting infrared light and a light receiving unit for receiving infrared light,
A potential type heart rate sensor having at least two electrodes provided on a steering wheel for detecting a driver's heart rate from a potential difference due to pulsation between both hands, and time series data of heart rate detected by the infrared heart rate sensor Heart rate data processing means for comparing the number of the heart rate data with the time series data of the heart rate detected by the potential type heart rate sensor and adopting the larger value as the effective heart rate. apparatus. 2. An infrared light emitting portion and an infrared light receiving portion at a position of a steering wheel that is frequently gripped by a driver, and at a contact position of a portion of the hand where the blood flow is large when the driver grips the steering wheel. A heartbeat sensor having a heartbeat sensor is provided, an elastic member is provided in the peripheral portion of the position where the heartbeat sensor is disposed, and the contact surface of the elastic member with the hand is formed to have a predetermined curvature in accordance with the partial shape of the contacting hand. Characteristic heart rate detector.