JP2020103495A - Method of monitoring autonomic nerve activity and system thereof - Google Patents

Abstract

To provide a method of accurately monitoring an autonomic nerve activity which exerts an influence on the operation behavior of an operator by a simple method, and a system thereof.SOLUTION: There are provided a method of monitoring an autonomic nerve activity which exerts an influence on the operation behavior of an operator, and a system thereof. The system comprises: a biological information measurement unit which respectively measures heart rate waveform data and aspiration waveform data being time waveforms of a heart rate and aspiration of the operator in a prescribed operation section; and a control unit which includes a determination device which extracts a parasympathetic nerve component of the heart rate waveform data by waveform variation in the aspiration waveform data and determines the state of the autonomic nerve activity of the operator.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method and system for monitoring a driver who is driving a vehicle, and more particularly to a method and system for monitoring autonomic nerve activity that affects the driving behavior of the driver.

Human autonomic nerves are composed of a sympathetic nervous system and a parasympathetic nervous system, and by maintaining these balance, the mind and body are maintained in a normal state. Here, the heart rate variability (variation in heart rate interval) has a component that reflects the activity of the sympathetic nervous system that reflects mental and physical tension and the activity of the parasympathetic nervous system that leads this function to a sedative state. It is said that the peak of the component that reflects the activity of the nervous system almost coincides with the respiratory cycle. Therefore, an attempt is made to capture changes in biological cycle information such as breathing and heartbeat of a driver driving a vehicle to determine the activity state of the driver's autonomic nerves, reflect the change in the driving control of the vehicle, or give an alarm. A system for doing so has been proposed.

For example, Patent Document 1 discloses a method of detecting a change in the heartbeat of a driver and detecting the activity state of the driver's autonomic nerves. Here, the heart rate of the driver is measured by measuring the driver's heartbeat using electrodes provided on the steering wheel of the vehicle, and detecting the gripping state of the steering wheel by providing a plurality of electrodes and imaging the driver's posture. According to the state of the person, the state of activity of the autonomic nerves, that is, the state in which attention is required for driving the vehicle, such as nervousness, drowsiness, irritability, fatigue, and vagueness (distraction), can be discriminated.

In addition, Patent Document 2 also discloses a method of determining based on a change in breathing and a change in driving state as a vehicle driving support method for determining the activity state of the driver's autonomic nerve and performing driving support. That is, the respiratory signal is extracted from the body pressure signal from the pressure sensor provided on the back of the seat and the traveling state amount of the accelerator and the brake to determine the "psychological upset degree" of the driver. Here, since the input signal of the body pressure includes the body pressure fluctuation based on the operation of the accelerator and the brake, the body pressure fluctuation based on the operation of the accelerator and the brake should be removed depending on the running state amount to obtain an accurate breathing signal. I am trying.

Further, in Patent Document 3, the beat-to-beat time (RRI), which is expected to appear the respiratory fluctuation in the measured heartbeat, is obtained by numerical filter processing, and whether the fluctuation state of the RRI is the normal driving state or not. , Or a wakefulness determination method that determines whether the wakefulness is an index of an activity state of an autonomic nerve such as “drowsiness” by detecting whether the consciousness is a simple increase or a simple decrease corresponding to a sudden change in mental load. doing. Here, the reference line f(n) corresponding to the fluctuation of the RRI is changed between the normal state and the simple increase or the simple decrease, and the variance RRVn of the RRI with respect to the reference line f(n) is calculated. However, it is said that the arousal level can be detected based on the distributed RRVn.

Japanese Patent No. 4739407 JP, 2006-042903, A JP, 2007-044154, A

As described above, there is an attempt to measure the heartbeat to monitor the autonomic nerve activity that affects the driving behavior of the driver, but here, signal processing using the respiratory cycle may be performed. On the other hand, since breathing changes depending on the will of the person, it is not easy to give the degree of accuracy that enables stable driving support.

The present invention has been made in view of the above circumstances, and an object thereof is a method and a method for accurately monitoring an autonomic nerve activity that affects the driving behavior of a driver with a simple method. To provide a system.

According to the present invention, a method for monitoring autonomic nerve activity that affects the driving behavior of a driver, measures heartbeat waveform data and respiratory waveform data, which are time waveforms of the driver's heartbeat and respiration in a predetermined driving section, respectively, and It is characterized in that the state of the autonomic nerve activity of the driver is discriminated by extracting the parasympathetic nerve component of the heartbeat waveform data according to the waveform change of the respiratory waveform data.

In addition, the monitoring system of the autonomic nerve activity that influences the driving behavior of the driver according to the present invention measures heartbeat waveform data and respiratory waveform data, which are time waveforms of the heartbeat and respiration of the driver in a predetermined driving section, respectively. A biological information measuring unit; and a control unit including a discriminating device for discriminating the state of the autonomic nerve activity of the driver by extracting a parasympathetic nerve component of the heartbeat waveform data by a waveform change of the respiratory waveform data. Is characterized by.

According to such an invention, the heartbeat and respiration are simultaneously measured as the biometric information of the driver, heartbeat information can be analyzed based on the respiration information by comparing these waveform data, and the autonomic nervous activity of the driver can be analyzed by a simple method. The state can be accurately discriminated or estimated.

In the invention of the method for monitoring the autonomic nerve activity or the system thereof, the control unit includes a database, and the heartbeat waveform data and the respiratory waveform data in the predetermined driving section are repeatedly acquired and accumulated, and the determination device is You may comprise so that the said waveform change of the said respiratory waveform data may be discriminate|determined based on the said database. At this time, it is preferable that the waveform change is based on a change in the amplitude or frequency of the respiratory waveform of the respiratory waveform data. According to this invention, it is possible to further improve the accuracy of discriminating the state of autonomic nerve activity.

In the invention of the method for monitoring an autonomic nerve activity or the system thereof, the biological information measuring unit may be configured to include a respiratory waveform measuring device for measuring the chest circumference of the driver to obtain the respiratory waveform data. Good. According to this invention, the heartbeat can be measured easily and accurately without significantly affecting the operation of the driver. At the same time, it becomes possible to measure the heartbeat and respiration at the same time and in the vicinity, and it is possible to reduce the size of the entire unit.

In the invention of the method for monitoring the autonomic nerve activity or the system thereof, it may be configured to notify the driver of the driving assistance information according to the determination result after the determination. According to this invention, it becomes possible to assist the driving by feeding back the discrimination result to the driving driver in real time.

1 is a block diagram showing an outline of a monitoring system according to a representative example of the present invention. Waveform data measured by the driver. Waveform data measured from another driver. It is an example of heartbeat fluctuation and frequency distribution of respiration. Here, (a) shows each example when the parasympathetic nervous system activity is dominant, and (b) shows each example when the parasympathetic nervous system activity decreases.

Specific embodiments of a driver monitoring method and system according to a representative example of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 1, a monitoring system 100 that monitors an autonomic nerve activity that influences a driver's driving behavior includes biometric information that measures time waveforms of a driver's heartbeat and respiration as biometric information of the driver. It includes a measurement unit 110 and a control unit 120 having a function of receiving the waveform data from the biological information measurement unit 110 and analyzing the waveform data.

The biological information measurement unit 110 is configured as, for example, a stretchable belt-shaped wearing device that can be worn on the driver's chest, and has a heartbeat measuring sensor 112 for measuring a heartbeat, a respiration detecting sensor 114 for measuring a respiration state, including. Here, the heartbeat measurement sensor 112 is composed of a plurality of electrocardiogram electrodes and the like, and the respiration detection sensor 114 is a respiratory waveform measurement composed of a displacement sensor or the like that detects a change in the driver's chest circumference, that is, the circumference of the chest. Composed of equipment. As a result, the biological information measuring unit 110 can measure the heartbeat and respiration at the same time and in the vicinity without significantly affecting the operation of the driver, and can reduce the size of the entire unit. it can.

The control unit 120 controls the overall operation of the monitoring system 100 shown in FIG. 1, and also controls the biological information measuring unit 110 to receive data by transmitting measurement data to the biological information measuring unit 110. A discriminating device 124 for discriminating the activity state of the driver's autonomic nerve by analyzing the generated waveform data, and a storage device 126 for storing the program executed by the discriminating device 124 and the waveform data received from the biological information measuring unit 110. including. The discriminating device 124 compares the heartbeat waveform data and the respiration waveform data of the same section in the measurement data measured by the biological information measuring unit 110 according to a predetermined discrimination program, for example, to determine the autonomic nerve activity state of the driver. To determine. That is, the state of the driver's autonomic nerve activity is determined by extracting the parasympathetic nerve component of the heartbeat waveform data based on the waveform change of the respiratory waveform data. Further, the control unit 120 may include an output device (monitor or the like) not shown.

The biological information measuring unit 110 and the control device 122 of the control unit 120 are connected by a signal line 130 that transmits an electric signal. Note that the signal line 130 is not limited to a wired connection, and the biological signal measuring unit 110 and the control unit 120 may be wirelessly connected to exchange a command signal and measurement data.

Next, a typical discrimination example by the discrimination method of the activity state of the autonomic nerve of the driver according to one embodiment of the present invention will be described.

Here, a simulated driving work using a driving simulator was carried out as an experiment for measuring biological information during the driving work of the driver. Specifically, a simple railway operation simulator composed of a large TV monitor and a one-handle controller was used, and commercially available railway operation simulation software was used for simulator control. In the experiment, the driver repeats a simulated running task (for example, an actual running program between a plurality of stations) a predetermined number of times while taking a break. At this time, the driver was instructed to drive within the speed limit according to the timetable during the experiment, and to apply the emergency brake and sound the horn in an emergency. Then, in order to obtain changes in the biological information in the driver's psychological agitation state, place an obstacle (for example, a fallen tree) in the track in the driving program, and set the time from when the obstacle is detected until the brake is operated. It was also measured.

2 and 3, the horizontal axis represents time. In (a), the vertical axis represents the number of heartbeats per predetermined time in a dimensionless manner. In (b), the vertical axis represents the change in electric potential due to respiration. Further, in (c), the strength of the brake (notch) operation is expressed dimensionlessly.

By the way, in estimating the driver's autonomic nervous activity, it is difficult to recognize the current situation when the driver is shaken, as in the expression "the head becomes pure white" when the person is psychologically disturbed. Therefore, an estimation method that does not rely on subjective evaluation is required. Here, the psychological process after the occurrence of the event causing the psychological agitation is roughly classified into a psychological process having no psychological agitation and a psychological process having a psychological agitation.

If psychological agitation does not occur, it is considered that the situation is calmly grasped and appropriate actions are taken, and the reaction of the autonomic nervous system is considered to be the reaction of the parasympathetic nervous system that is relatively focused on collecting information. .. On the other hand, when psychological agitation occurs, it is considered that the nerve becomes excited and the sympathetic nervous system becomes dominant. Actually, “Type A” is a suitable action such as situational grasp without any psychological agitation, and “Type B” is a temporary psychological agitation, which is promptly recovered and transferred to an appropriate action. It is considered that there are three types, “Type C” in which psychological agitation lasts.

As shown in FIG. 2, first, according to the measurement data of the driver as the first test subject, the braking operation is immediately executed immediately after the obstacle is found at the time T when the obstacle is found. At this time, activation of the sympathetic nervous system was temporarily observed, in which the heart rate increased immediately after the obstruction was detected, and the amplitude center of breathing once shifted to the negative side and the interval became slightly shorter. A parasympathetic response was obtained in which the heart rate decreased and the breathing interval increased to return to a steady state.

In this way, by measuring the driver's breathing in real time and using the change in the amplitude or frequency of the waveform data (waveform change) as the starting point, the section in which the sympathetic nervous system is dominant in the heartbeat waveform data (sympathetic nerve It is possible to separately extract the component) and the section in which the parasympathetic nervous system is dominant (parasympathetic nervous component). That is, it becomes possible to more accurately grasp the timing of the activity of the parasympathetic nervous system of the autonomic nerve, as compared with the case where the conventional measurement of the waveform data of the heartbeat is detected. Then, from the waveform data of the heartbeat and respiration shown in FIG. 2, the first driver can determine that the above-mentioned “type B” type is applicable.

On the other hand, as shown in FIG. 3, according to the measurement data of the driver as the second test subject, the braking operation is performed about 3 seconds after the obstacle is found at the time T when the obstacle is found. There is. In addition, immediately after the obstacle is detected, the heart rate rises and the high heart rate continues for about 20 seconds, and the breathing interval becomes short (or random) and the amplitude decreases (that is, breathing becomes shallow). ), the reaction in which the sympathetic nervous system was dominant continued.

In this way, if the driver's breathing disturbance lasts for a certain period of time, it means that the section in which the sympathetic nervous system is dominant in the heartbeat waveform data is long and the parasympathetic nervous system is dominant. Therefore, it is possible to detect that the start of recovery activity by the autonomic nerve is delayed. That is, even if the driver has psychological agitation, by comparing the waveform data of heartbeat and breath, it is possible to grasp the timing of the psychological state recovery due to the activity of the parasympathetic nervous system. From the waveform data of the heartbeat and respiration shown in FIG. 3, it can be determined that the above-mentioned “type C” type is applicable.

As described above, by comparing the heartbeat and respiratory waveform data for the same driver at the same time in a predetermined driving section, the parasympathetic nerve component in the heartbeat waveform data is extracted, and the state of psychological sway (that is, in heartbeat activity) is extracted. This is preferable because the degree of influence and change of the respiratory component can be visualized. As a result, it becomes possible to discriminate the driver's autonomic nerve activity state and its type. In addition, such data is repeatedly acquired for the same driving section, or acquired for many drivers and stored in a database to improve the accuracy of the determination of the activity state of the autonomic nerve. It is also possible.

FIG. 4 shows an example of visualization. FIG. 4A shows a waveform when parasympathetic nervous system activity is dominant, and FIG. 4B shows a waveform when parasympathetic nervous system activity is reduced. Here, the horizontal axis represents frequency, and the vertical axis represents power spectral density (PSD) of heartbeat and respiration in a dimensionless manner. As can be seen from this, it becomes possible to easily grasp the state of parasympathetic nervous system activity from changes in the heartbeat fluctuation component in the peak frequency band of respiration.

Further, in the monitoring system 100 shown in FIG. 1, the control unit 120 may be provided with an output device such as a monitor, and the driver may be notified of the driving assistance information according to the determination result of the determination device 124. At this time, as the driving assistance information, a status display indicating that the driver is in an excited state, a warning display prompting a brake operation, or an auxiliary procedure display teaching a procedure for returning to a steady driving state can be considered. As a result, it is possible to assist the driving by feeding back the discrimination result to the driving driver in real time, and to use the biometric information and the discrimination result accumulated for each driver in the past for the assisting function of the driver. Become.

According to the monitoring method and the system for monitoring the autonomic nerve activity that affects the driving activity of the driver according to the above-described embodiment, the change in the waveform is read from the respiratory waveform data obtained from the biological information measuring unit, and simultaneously measured. Among the fluctuation components of the heartbeat waveform data obtained from the electrocardiogram, it is possible to accurately calculate the component that reflects the activity of the parasympathetic nervous system that occurs in the vicinity of the respiratory cycle. The state of autonomic nerve activity of the driver can be accurately discriminated or estimated by using a simple method. In addition, by measuring and accumulating the heart rate variability and respiratory cycle/strength within an individual over time, the change pattern corresponding to the activity state of the autonomic nerve within the individual is extracted, and the autonomic nerve utilizing the electrocardiogram and respiratory waveform is extracted. It is also possible to improve the discrimination accuracy in estimating the state of activity.

According to the above respiratory waveform analysis, it can be used not only for autonomic nervous system activity but also for estimating a psychological state.

Although the representative embodiment according to the present invention has been described above, the present invention is not necessarily limited to this, and can be appropriately changed by those skilled in the art. Thus, one of ordinary skill in the art will be able to find various alternatives and modifications without departing from the scope of the appended claims.

100 Monitoring System 110 Biological Information Measuring Unit 112 Heart Rate Measurement Sensor 114 Respiration Detection Sensor 120 Control Unit 122 Control Device 124 Discrimination Device 126 Storage Device

Claims (10)

A method of monitoring autonomic nervous activity that affects the driving behavior of a driver,
The heartbeat waveform data and the respiratory waveform data, which are time waveforms of the heartbeat and respiration of the driver in a predetermined driving section, are measured, and the parasympathetic nerve component of the heartbeat waveform data is extracted by the waveform change of the respiratory waveform data to perform the driving. A method for monitoring autonomic nerve activity, comprising determining the state of the autonomic nerve activity of a person. The method for monitoring autonomic nerve activity according to claim 1, wherein the heartbeat waveform data and the respiratory waveform data in the predetermined operation section are repeatedly acquired to determine the waveform change of the respiratory waveform data. The method for monitoring autonomic nerve activity according to claim 2, wherein the waveform change is based on a change in amplitude or frequency of a respiratory waveform of the respiratory waveform data. The method for monitoring autonomic nerve activity according to claim 1, wherein the respiratory waveform data is acquired by measuring a chest circumference of the driver. The method for monitoring autonomic nerve activity according to claim 1, wherein the driver is notified of the driving assistance information based on the discrimination in the parasympathetic nerve component of the extracted heartbeat waveform data. A monitoring system for autonomic nervous activity that affects the driving behavior of a driver,
A biological information measuring unit that measures heartbeat waveform data and respiratory waveform data, which are time waveforms of the heartbeat and respiration of the driver in a predetermined driving section, respectively,
A control unit including a discriminating device for discriminating the state of the autonomic nerve activity of the driver by extracting a parasympathetic nerve component of the heartbeat waveform data by a waveform change of the respiratory waveform data,
A monitoring system for autonomic nervous activity, characterized by being equipped with. The control unit includes a database and repeatedly acquires and stores the heartbeat waveform data and the respiratory waveform data in the predetermined operation section, and the determination device determines the waveform change of the respiratory waveform data based on the database. The monitoring system for autonomic nervous activity according to claim 6, wherein: The system for monitoring autonomic nervous activity according to claim 7, wherein the waveform change is based on a change in amplitude or frequency of a respiratory waveform of the respiratory waveform data. 9. The autonomic nerve activity according to claim 6, wherein the biological information measuring unit includes a respiratory waveform measuring device that measures the driver's chest circumference and acquires the respiratory waveform data. Monitoring system. 10. The autonomic nerve activity monitoring system according to claim 6, wherein the driver is notified of the driving assistance information based on the discrimination in the parasympathetic nerve component of the extracted heartbeat waveform data.