JPH0759757A - Physical condition detector - Google Patents

Abstract

PURPOSE:To provide a physical condition detector which enables the analyzing of fatigue of a testee to accomplish accurate judgment. CONSTITUTION:A microwave is transferred to or from an operator by a microwave displacement meter 1 and a displacement signal obtained with a detection signal computing circuit 2 is applied to a zero cross cycle counter 4 passing through a zero cross detector 3 to detect the cycle of heart beats. After the detection of a changing ratio of the cycle of the heart beats with a CPU6, detection values are compared with a reference value predetermined to judge the physical condition of the testee being examineal in a plurality of stages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a physical condition detecting device for detecting physical condition such as physical fatigue of a subject.

[0002]

2. Description of the Related Art As a conventional body condition detecting apparatus of this type, there is one disclosed in, for example, Japanese Patent Laid-Open No. 1-134344. This is to receive the reflected microwaves from the chest or abdomen of the subject by irradiating the subject with microwaves, and the period of the signal obtained by calculating the received signal after detection, the amplitude or the predetermined period, The maximum value of the signal obtained as the above calculation, by comparing at least one value of the minimum value with a predetermined value, to detect the respiratory cycle and size of the subject, the physical fatigue state of the subject It is something to detect.

[0003]

However, in the case of the conventional physical condition detecting device of this type, the physical fatigue condition of the subject does not have a great influence on the work. Fatigue state) or static physical fatigue state (state of physical and mental fatigue due to lack of sleep or mental stress) that has a great impact on work due to judgment loss. There is a problem in that it cannot be determined.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a body condition detecting device capable of subdividing a physical fatigue condition of a subject and accurately discriminating it. To provide.

[0005]

In order to achieve the above object, the present invention provides an electromagnetic wave transmitting / receiving sensor which irradiates an electromagnetic wave to a subject and receives a reflected electromagnetic wave from the chest or abdomen of the subject. A displacement amount calculating means for calculating a displacement amount of the chest or abdomen of the subject based on a received signal of the electromagnetic wave transmitting and receiving sensor, and a heart rate or a respiratory rate based on the displacement amount calculated by the displacement amount calculating means. Probabilistic variation rate, variation rate calculation means for calculating the average value of the heartbeat cycle or respiratory cycle, comparison calculation of the value calculated by the variation rate calculation means and a predetermined reference value, and the result of comparison calculation And a state detecting unit for detecting a fatigue state and an awake state of the subject.

[0006]

In the body condition detecting device according to the present invention, the displacement amount calculating means calculates the displacement amount of the chest or abdomen of the subject based on the received signal of the electromagnetic wave transmitting / receiving sensor, and the fluctuations are caused by the calculated displacement amount. The stochastic fluctuation rate of the heart rate or respiratory rate and the average value of the heartbeat cycle or the respiratory cycle are calculated by the rate calculation means, and the calculated value is compared and calculated with a predetermined reference value in the state detection means. Since the fatigue state and the awake state of the physical condition of the subject are detected from the result of the comparison calculation, the physical fatigue state of the subject can be subdivided and accurately determined.

[0007]

1 is a block diagram showing a system configuration of a first embodiment of a vehicle occupant state detecting apparatus to which a body state detecting apparatus of the present invention is applied.

The vehicle occupant state detection apparatus of the first embodiment irradiates a driving vehicle P as a subject with microwaves and receives microwaves reflected from the chest or abdomen of the driver P as a microwave displacement. The state of the driver P is detected based on the received signals from the total 1.

Therefore, the detection signal arithmetic circuit 2, the zero-cross detector 3, the zero-cross cycle counter 4, the reference frequency oscillator 5, and the CPU 6 are provided.

The detection signal calculation circuit 2 detects the received signal from the microwave displacement meter 1, and based on the detection signal, the chest 2 or abdomen of the driver P and the epidermis surface of the chest or abdomen due to movement of blood vessels. The displacement amount according to the displacement of is calculated.

The zero-cross detector 3 detects each point where the reflected microwave crosses the reference line by the signal calculated by the detection signal calculation circuit 2.

The zero-cross cycle counter 4 detects the cycle of the heartbeat of the driver P by comparing the positions of the intersections obtained from the respective points detected by the zero-cross detector 3 with the reference frequency from the reference frequency oscillator 5. .

The CPU 6 uses the zero-cross cycle counter 4
The average value of the heart rate of the driver P and the stochastic fluctuation rate of the heartbeat cycle are calculated from the cycle of the heartbeat of the driver P detected in step S1, and the calculated value is compared with a predetermined reference value. The average value of the heart rate of the driver P and the stochastic fluctuation rate of the heartbeat cycle are detected in a plurality of stages, and the detected values obtained by the comparison calculation are the dynamic physical fatigue or the static physical fatigue of the driver P, respectively. When an abnormality corresponding to is indicated, the abnormality notification signal indicating the dynamic physical fatigue or the abnormality notification signal indicating the static physical fatigue is output to the alarm device 7. That is, the displacement state detecting means is constructed by a combination of the zero cross detector 3, the zero cross cycle counter 4, the reference frequency oscillator 5, and the CPU 6,
The physical condition determination means is constructed only by the CPU 6. The alarm device 7 issues an alarm of the dynamic physical fatigue when the CPU 6 receives the abnormal alarm signal of the dynamic physical fatigue from the CPU 6, and receives the abnormal alarm signal of the static physical fatigue from the CPU 6. When it does, it gives a warning of static physical fatigue. For example, in the case of dynamic physical fatigue, a slight warning (point of a warning lamp, etc.) is issued because recovery can be recovered immediately after a short rest. On the other hand, in the case of static physical fatigue, unless a long rest is taken, driving becomes slow and dangerous, and a warning sound such as a buzzer is emitted. Further, when the static physical fatigue is mild and the arousal state tends to decrease, a light warning sound is emitted, and when the static physical fatigue is high and the awake state significantly decreases, an alarm sound such as a buzzer is emitted.

FIG. 2 is a block diagram showing a system configuration of a second embodiment of a vehicle occupant state detecting apparatus to which the body state detecting apparatus of the present invention is applied.

The vehicle occupant state detecting device of the second embodiment employs a zero cross frequency counter 8 instead of a combination of a zero cross period counter and a reference frequency oscillator, and each of the zero cross detectors 3 detects. The frequency represented by the point is detected by the zero-cross frequency counter 8. Then, the CPU 6 detects the average value of the heart rate of the driver P and the stochastic fluctuation rate of the heartbeat cycle in stages from each frequency corresponding to the driver P detected by the zero-cross frequency counter 8. However, when the detected value obtained by this comparison operation indicates an abnormality corresponding to the dynamic physical fatigue or the static physical fatigue of the driver P, the alarm device 7 is notified of the dynamic physical fatigue as in the embodiment of FIG. An abnormality notification signal indicating the effect or an abnormality notification signal indicating the effect of static physical fatigue is output. Note that, in FIG. 2, the parts denoted by the same reference numerals as those in FIG. 1 indicate the corresponding parts.

Next, the operation of the first and second embodiments of the present invention will be described.

First, the relationship between the physical condition of the driver P and the heartbeat condition will be described with reference to FIGS. However, FIG. 3 is a time-series data characteristic diagram showing an example of a temporal change of a heartbeat cycle at the time of transition to a decline in awake state, and FIG. 4 is a characteristic diagram showing an example of a respiratory cycle and a probability density distribution in a normal state, FIG. 7 is a characteristic diagram showing an example of the respiratory cycle and the probability density distribution when the decrease in the arousal state is mild, and FIG. 6 is a characteristic diagram showing an example of the respiratory cycle and the probability density distribution when the decrease in the awake state is high. Is a characteristic diagram showing an example of dynamic physical fatigue and a tendency of recovery thereof, and FIG. 8 is a characteristic diagram showing an example of static physical fatigue and a tendency of recovery thereof.

When the driver P shifts from the normal state to the lowered awake state as shown in FIG. 3, the heart rate and the fluctuation rate temporarily increase as compared with the awake state, but the heart rate gradually increases. The rate of pulsation decreases and the rate of fluctuation of the heartbeat cycle also decreases.

When in a dynamic fatigue state as shown in FIG. 7 due to heavy exercise or the like, the heart rate increases and the fluctuation rate of the heartbeat cycle tends to decrease as compared with the normal state. , You can recover after a short break (about 10 minutes).

When the body is in a static physical fatigue state as shown in FIG. 8 due to lack of sleep or the like, the heart rate decreases as compared with the normal state, but the fluctuation rate increases. In this case, even if you take a break for about 30 minutes, you will not recover.

FIG. 9 is a vector representation of the principle of body condition detection. The vertical axis represents the average value of the heart rate, and the horizontal axis represents the fluctuation rate of the heart rate. Static fatigue resulting from mental stress is represented by a vector, dynamic fatigue resulting from physical labor is represented by a vector, and arousal (REM) sleep is represented by a vector. In addition, non-wakeful sleep (non-REM) sleep refers to a state when there is a vector in the third quadrant. Table 1 shows a summary of this graph.

[0022]

[Table 1] By detecting the above tendency from the heartbeat state of the driver P,
The physical condition of the driver P can be known. By observing the breathing state instead of the heartbeat state of the driver P,
The physical condition of the driver P can be known.

Next, the operation of the vehicle occupant state detection apparatus of the first embodiment shown in FIG. 1 to which the body state detection apparatus of the present invention is applied will be described with reference to the flowchart of FIG.

Based on the received signal from the microwave Doppler sensor 1 installed toward the body of the driver P, the detection signal operation circuit 2 measures the distance γ to the body surface of the driver P after detection (step 901). This minute change in the distance γ serves as a received heart signal due to the heartbeat, and each point at which the microwave reflected by the zero cross detector 3 crosses the reference line is detected from this displacement signal. The cycle T of the heartbeat of the driver P can be detected by comparison with the reference frequency (step 902).

The thus detected heartbeat cycle of the driver P is fetched by the CPU 6, and the CPU 6 obtains the fluctuation rate σ of the heartbeat cycle from the change with time of the heartbeat cycle of the driver P (step 903). On the other hand, the CPU 6 previously stores and holds the average value of the heartbeat cycle of the driver P in the normal state as T ₀ , and the variation rate of the heartbeat cycle of the driver P in the normal state is σ.
It is stored and held in advance as ₀ .

Therefore, the CPU 6 compares the detected heartbeat cycle T with the heartbeat cycle T ₀ stored in advance (step 904) and, if T is not larger than T ₀ , calculates based on the detection. The fluctuation rate σ of the heartbeat cycle is compared with the fluctuation rate σ _{0 of the} heartbeat cycle which is stored in advance (step 905), and if σ is smaller than σ _0, it is determined to be dynamic physical fatigue (step 906), and a warning is issued. The light is turned on (step 907). The lighting of this warning light means a "light warning". In other words, the dynamic physical fatigue state does not affect the driving of the vehicle so much, and therefore the warning is limited to a light warning light.

Further, if T is larger than T ₀ at step 904, it is determined whether sigma is greater than sigma ₀ (step 908), if the sigma is greater than sigma ₀ is the static body It is determined to be fatigued (step 909), the warning chime is sounded, and at the same time, the warning light is turned on (step 91).
0). The notification by the warning chime and the warning light means "ordinary warning". In other words, the static physical fatigue state is
Since the judgment of the driver P may be overwhelmed, it means that it is better to take a rest for a while.

If T is larger than T ₀ in step 904 and σ is smaller than σ _{0 in} step 908, it is judged that the awakening state is significantly lowered (step 911) and the warning buzzer is activated. At the same time, the alarm lamp is turned on to give a strong warning (step 912). The notification by the warning buzzer and the warning light means “heavy warning”.

As described above, since the alarm content can be subdivided with high accuracy according to the physical condition of the driver P, static physical fatigue takes longer than recovery from dynamic physical fatigue (see FIGS. 7 and 8).
In the event of occurrence of, the driver P can be warned to interrupt or stop the driving of the vehicle.

The operation of the vehicle occupant state detecting apparatus of the first embodiment shown in FIG. 1 has been described above with reference to the flow chart. However, the operation of the vehicle occupant state detecting apparatus of the second embodiment shown in FIG. Since a similar operation is performed, it is omitted here. In each of the above-described embodiments, the driver P
Although the physical condition of the driver P is detected based on the heartbeat detection, the physical condition of the driver P can be detected by detecting the breathing condition of the driver P. In this case, the breathing state is more practical than the heartbeat, and is advantageous in that it has a large displacement amount.

In each of the embodiments described above, the body condition of the driver is detected when the vehicle is driving. However, the body condition detecting device of the present invention reduces the dynamic or static physical fatigue or awake state. It is needless to say that the present invention can also be applied to the case of detecting the physical condition of a worker or the like who works at a work site where there is a risk of erroneous work.

Further, the physical condition detecting device of the present invention detects the physical condition of the subject by two parameters of the stochastic rate of change of the heart rate or respiratory rate of the subject and the average value of the heartbeat period or respiratory synchronization. Since the calculation method is introduced, an electromagnetic wave transmission / reception sensor such as a microwave displacement meter that can suppress an increase in the number of parts and that is relatively easy to miniaturize can be applied as a means for heartbeat detection or respiration detection. The whole system can be made simple and small.

[0033]

As described above, according to the present invention, the physical condition of the subject is detected by the stochastic fluctuation rate of the subject's heart rate or respiratory rate and the average value of the heartbeat period or the respiratory period. Therefore, the physical fatigue of the subject can be accurately subdivided and detected, such as dynamic physical fatigue, static physical fatigue, and deterioration of arousal state, and a warning corresponding to each fatigue state can be given. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a first embodiment of a vehicle occupant state detection device to which a body state detection device of the present invention is applied.

FIG. 2 is a block diagram showing a system configuration of a second embodiment of a vehicle occupant state detection device to which the body state detection device of the present invention is applied.

FIG. 3 is a time-series data characteristic diagram showing an example of changes in the heart rate, the heart rate, and the fluctuation rate of the heartbeat cycle when the awake state shifts to a decrease.

FIG. 4 is a characteristic diagram showing an example of dispersion of heartbeat cycles in a normal state.

FIG. 5 is a diagram showing an example of the variance of the heartbeat cycle when the awake state is mildly decreased.

FIG. 6 is a diagram showing an example of dispersion of heartbeat cycles when the wakefulness is significantly lowered.

FIG. 7 is a characteristic diagram showing an example of a dynamic physical fatigue state and its recovery tendency.

FIG. 8 is a characteristic diagram showing an example of a static body fatigue state and a tendency of its recovery.

FIG. 9 is a flowchart showing the operation of the vehicle occupant state detection device to which the present invention is applied.

FIG. 10 is a vector display diagram showing the principle of body condition detection.

[Explanation of symbols]

 1 Microwave displacement meter 2 Detection signal calculation circuit 3 Zero cross detector 4 Zero cross counter 5 Reference frequency oscillator 6 CPU 7 Alarm device 8 Zero cross frequency counter

Claims (1)

[Claims] 1. An electromagnetic wave transmission / reception sensor for irradiating an electromagnetic wave to a subject and receiving a reflected electromagnetic wave from the chest or abdomen of the subject, and a signal of the subject based on a received signal from the electromagnetic wave transmission / reception sensor. A displacement amount calculation means for calculating the displacement amount of the chest or abdomen, a stochastic variation rate of the heart rate or respiratory rate based on the displacement amount calculated by the displacement amount calculation means, and an average value of the heartbeat cycle or the respiratory cycle are shown. A state-of-change detecting means for calculating and a state of detecting a fatigue state and an awake state of the subject from the result of the comparison calculation by comparing the value calculated by the variation-rate calculating means with a predetermined reference value. And a body condition detecting device.