JP2007125279A - Living body state determination device and residence system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is difficult to determine a living body state in a conventional living body state determination device when the peak of a biological signal waveform or the waveform of change in time series of a calculated Lyapunov exponent is not clear in response to the state of a living body. <P>SOLUTION: The living body state determination device can easily determine the state of the living body by determining the physiologic and psychologic state of the living body based on at least either one of the average value or standard deviation of the calculated Lyapunov exponents. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a biological state determination apparatus that determines a state of a biological body by performing chaos analysis on a biological signal.

The peak value of each cycle of the biological signal data and the Lyapunov exponent are calculated by performing chaos analysis on the biological signal data, and the peak value of each cycle of the time-series change waveform of the calculated Lyapunov exponent is calculated. There is a living body state determination device that detects a time when the rate of time change of any one of the values suddenly decreases to determine the state of a living body, in particular, the sleep of the living body. (For example, refer to Patent Document 1).
JP 2004-344612 A

  However, the above-described conventional biological state determination device has a problem that it is difficult to determine if the biological signal waveform or the peak of the time-series change waveform of the calculated Lyapunov exponent may not be clear depending on the state of the biological body. Moreover, in calculating the peak value, complicated calculations such as identification of each cycle and search for the peak are necessary, and there is a problem in simplicity as an apparatus.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a biological state determination apparatus that easily determines a biological state by performing chaos analysis on a biological signal.

  In order to solve the above-described conventional problems, a biological state determination apparatus according to the present invention calculates a biological signal detection unit that detects a biological signal of a biological unit and a Lyapunov exponent of biological signal data detected by the biological signal detection unit. A Lyapunov exponent calculating means, a signal analyzing means for calculating at least one of an average value and a standard deviation of an output signal of the Lyapunov exponent calculating means, and a physiological and psychological state of the living body based on an output signal of the signal analyzing means Determination means. Then, the physiological and psychological state of the living body is determined based on at least one of the calculated average value and standard deviation of the Lyapunov exponent.

  Since the physiological and psychological state of the living body is determined based on at least one of the calculated average value and standard deviation of the Lyapunov exponent, a biological state determination device that easily determines the state of the living body can be realized.

  According to a first aspect of the present invention, there is provided a biological signal detection means for detecting a biological signal of a biological body, a Lyapunov exponent calculation means for calculating a Lyapunov exponent of biological signal data detected by the biological signal detection means, and an output of the Lyapunov exponent calculation means. And a signal analyzing unit that calculates at least one of an average value and a standard deviation of the signal, and a determining unit that determines a physiological and psychological state of the living body based on an output signal of the signal analyzing unit. Then, the physiological and psychological state of the living body is determined based on at least one of the calculated average value and standard deviation of the Lyapunov exponent. Since the state of the living body is determined only by such simple arithmetic processing, the determination result can be used immediately in accordance with the living situation, and the usability of the apparatus is increased.

In the second invention, in particular, the biological signal detection means of the first invention is a support that can support a living body such as a seat, a bed, a bathtub, a floor, or a toilet seat, or a living body such as clothes, glasses, shoes, a belt, or a portable information terminal. Is installed in at least one portable device that can be worn or carried, and detects a body motion signal synchronized with at least one of heartbeat and respiration of a living body as a biological signal, and directly detects heartbeat and respiration. A biological signal can be easily detected without attaching an electrode directly to a living body and detecting it like time.

  In particular, the biological signal detection means is provided on the support device or the portable device so as to detect the biological signal by transmitting the vibration indirectly by contacting or pressing the living body. In particular, there is no load on the living body.

  In the third aspect of the invention, the biological signal detecting means of the second aspect of the invention comprises a cable-like piezoelectric sensor and a sitting tool incorporating the piezoelectric sensor. Thus, a body motion signal synchronized with at least one of the heartbeat and respiration of the living body can be detected. As described above, as long as the sitting body supports the living body in a state in which a load is always applied when normally used in daily life, the sitting room is not limited to the sitting room.

  According to a fourth aspect of the present invention, in the biological state determination device according to any one of the first to third aspects of the present invention, the biological state determination apparatus includes comparison means for determining whether the biological signal data is within a preset setting range, and the Lyapunov exponent calculation Since the means calculates the Lyapunov exponent based on the determination result of the comparison means, for example, when the biological signal data is not within the preset setting range, such as when movement of limbs or posture changes, the Lyapunov index is calculated. Since the exponent may change suddenly and show an abnormal value, the Lyapunov exponent is not calculated. Also, the Lyapunov exponent is not calculated even when there is no living body and there is almost no signal level. This improves the reliability of Lyapunov exponent calculation.

  The fifth aspect of the invention is a control means for controlling home appliances and equipment installed in an environment where a living body lives based on the output signals of the signal analysis means and the determination means of any one of the first to fourth aspects of the invention. It is a living system provided. Thereby, a living environment can be controlled and the state of a biological body can be operated to an appropriate physiological and psychological state.

  In the sixth aspect of the invention, in particular, the control means of the fifth aspect of the invention controls home appliances and equipment so as to increase at least one of the average value and the standard deviation calculated by the signal analysis means. By increasing at least one of the average value and the standard deviation calculated by the signal analysis means, the activity of the brain of the target living body is increased, the fatigue level is reduced, or both are improved. The combined physiological and psychological state can be controlled.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram of a biological state determination apparatus according to a first embodiment of the present invention. In the figure, the biological signal detection means 1 includes a nonwoven fabric sheet 3 in which a cable-like piezoelectric sensor 2 is sewn and fixed with an automatic sewing machine, a cover member 4 that covers the nonwoven fabric sheet 3, and an amplifier unit 5 in which both ends of the piezoelectric sensor 2 are connected. A cushion-type main body 6 (sitting). Here, a sitting tool such as a cushion provided as a main body has a part that comes into contact with a living body at the time of use, and since the contacting part is loaded, the built-in biological signal detecting means is indirectly pressed against the human body. It becomes a state and becomes a structure which can detect a biological signal reliably. The amplifier unit 5 is fixed near the end of the nonwoven fabric sheet 3 and includes a filter circuit and an amplifier circuit that extract a body motion signal synchronized with the heartbeat of the living body from the output signal of the piezoelectric sensor 2. Since both ends of the piezoelectric sensor 2 are connected to the amplifier unit 5, even if the piezoelectric sensor 2 is disconnected halfway, the detection operation can be continued, and the configuration is redundant.

The natural frequency of the human body as a living body is distributed to about 4 to 6 Hz although it depends on the physique.
When a human body is to be detected, it is desirable that the filter circuit used in the amplifier unit 5 is a band-pass filter that mainly passes a 4 to 6 Hz signal. In addition, since the natural vibration at the installation location such as a chair where the main body 6 is installed becomes noise, if the natural vibration at the installation location is known in advance, the natural frequency that causes such noise from the output signal of the piezoelectric sensor 2. It is preferable to add a band elimination filter that removes. Furthermore, the signal level of the body motion signal may be too low or too high due to individual differences. For example, an auto switch that adjusts the amplification factor of the amplifier circuit to prevent the signal from being saturated by pressing a dedicated switch. A gain control function may be added to the amplifier circuit.

  A lead wire 7 is connected to the amplifier unit 5, and the lead wire 7 is detachably connected to the determination unit 8. The determination unit 8 includes a comparison unit 9, a Lyapunov exponent calculation unit 10, a signal analysis unit 11, a determination unit 12, a storage unit 13, and a display unit 14.

  The effect | action by the said structure is demonstrated. For example, when the main body 6 is installed on a chair, when a person as a living body sits on the main body 6, the piezoelectric sensor 2 is deformed by the body movement of the person, and the piezoelectric sensor 2 generates a voltage signal corresponding to the deformation acceleration by the piezoelectric effect. Is output. Then, a body motion signal synchronized with the human heartbeat is extracted from the output signal of the piezoelectric sensor 2 by the amplifier unit 5. FIG. 2 shows an example of a body motion signal waveform output from the amplifier unit 5 when a person is sitting at rest. From FIG. 2, it can be seen that a peak synchronized with the heartbeat appears in the body motion signal with a period of about 1 Hz based on a wave of several Hz.

  Next, operations of the comparison unit 9, the Lyapunov exponent calculation unit 10, the signal analysis unit 11, the determination unit 12, the storage unit 13, and the display unit 14 will be described based on the flowchart of FIG. First, at step S1, the analog output signal of the amplifier unit 5 is AD-converted at a predetermined sampling rate by the comparison means 9 to generate digital data. Based on this digital data, an integral value X per unit time is calculated and compared with a preset set value X1. Here, if X1 <X, the process proceeds to step S2, where X is compared with a preset set value X2. If X <X2, it is determined in step S3 that a person is present in the chair and is in a seated state. In step S4, the Lyapunov exponent calculation means 10 calculates the Lyapunov exponent using the digital data, and the storage means 13 Are stored in time series. Note that X is obtained by integrating the absolute value of the signal waveform with respect to the reference potential of the output signal of the amplifier unit 5 per unit time. X2 is set as a value larger than X1.

  If X1 <X is not satisfied in step S1, the comparison means 9 determines in step S5 that no person is present in the chair. If X <X2 is not satisfied in step S2, it is determined in step 6 that the person in the chair changes the movements and postures of the limbs and the rough movement has occurred by the comparison means 9. If it is determined that rough body movement has occurred, the calculation of the Lyapunov exponent by the Lyapunov exponent calculation means 10 is suspended in step 7, and the calculation value of the Lyapunov exponent before the occurrence of the rough body movement is used as a storage means. 13 is stored. Then, when the process proceeds from step S4 and step 7 to step S8, at least one of the average value and the standard deviation of the Lyapunov exponent is calculated by the signal analysis means 10, and based on these, the determination means 12 determines the physiological and psychological state of the person in step S9. Determined. And the determination result of the determination means 12 is displayed on the display means 14 by step S10. If it is determined in step S5 that no person is present in the chair, the absence is displayed by the display unit 14 in step S10. If necessary, the output signals of the comparison means 9, Lyapunov exponent calculation means 10, and signal analysis means 11 can be stored in the storage means 13. A series of processing flow as described above is repeated from step S1.

Here, the determination method of the physiological psychological state by the determination means 12 is demonstrated. FIG. 4 shows the result of calculating the Lyapunov exponent of the subject before and after the stress test using this embodiment. The Lyapunov index showed a higher value after the test than before the test, and it is thought that the brain activity increased due to the stress test. The standard deviation of the Lyapunov exponent in the same subject was 0.87 before the test and 1.00 after the test. This is considered to indicate that the body's ability to respond to various changes in the outside world was reduced because the body was fatigued by the test. These are consistent with the fact that the subject stated a reflection after the test, such as “I was tired but my head was scared”, and the physiological and psychological state of the living body can be determined from the average value and standard deviation of the Lyapunov exponent. Suggests the possibility.

  Based on the above, it can be considered that the average value of the Lyapunov exponent and the brain activity have the relationship of FIG. 5, and the standard deviation of the Lyapunov exponent and the fatigue level have the relationship of FIG. Accordingly, the determination means 12 determines the brain activity level and the fatigue level from the average value and standard deviation of the Lyapunov exponent based on the relationship shown in FIGS.

  FIG. 7 is a characteristic diagram in which the physiological state is divided into four states based on the average value and standard deviation of the Lyapunov exponent. Higher Lyapunov exponents mean higher brain activity, and greater standard deviation reduces fatigue. Each index was divided into two stages, and four matrices were provided. Specifically, in the figure, I is in the best state with the brain activated and not fatigued, II is in a state where the head is frightened but the body is tired, and III is when waking up asleep Brain activity is low but no fatigue, and IV is the worst state with low brain activity and fatigue. In this way, by making a determination based on FIG. 7, the position of the physiological and psychological state can be easily determined, so that it is easy to use and the state to be targeted becomes clear, which can contribute to taking breaks and improving life. .

  With the above action, the physiological state of the living body is determined based on at least one of the calculated average value and standard deviation of the Lyapunov exponent, so that a biological state determination device that easily determines the state of the living body can be realized.

  In addition, it is possible to detect a biological signal simply without attaching the electrode directly to the living body and detecting the heartbeat or respiration directly.

  Moreover, a body motion signal synchronized with at least one of heartbeat and respiration of a living body can be detected by a piezoelectric sensor simply by sitting on a cushion-type body as a sitting tool. In this way, in the case of a sitting tool or the like, it receives a biological load, inevitably the biological signal detection means is indirectly pressed, and body movement can be reliably detected. There is no need to wear tools and there is no load on the living body.

  Also, if the vital sign data is not within the preset setting range, such as when limb movement or posture change occurs, the Lyapunov exponent may change suddenly and show an abnormal value. Do not calculate. Also, the Lyapunov exponent is not calculated even when there is no living body and there is almost no signal level. This improves the reliability of Lyapunov exponent calculation.

  This is because, in order to calculate the Lyapunov exponent, data for a certain period of a biological signal when the living body is in a calm state that is calm to some extent is required.

  The determination unit 8 may also be used as a part of a portable information terminal such as a mobile phone or a PDA, a personal computer, or the like.

  In this embodiment, each index is divided into two stages and four matrices are provided. However, the present invention is not limited to this, and an appropriate matrix configuration for grasping the physiological and psychological state of a living body that is a detection purpose. You can do it.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 8A is a block diagram of the biological state determination apparatus according to the second embodiment of the present invention, and FIG. 8B is a block diagram of the amplifier unit 5. This embodiment is different from the first embodiment in that the amplifier unit 5 includes a comparison unit 9 and a Lyapunov exponent calculation unit 10, and the calculated Lyapunov exponent is transmitted to the center via the communication units 15 and 16. The server 17 is transmitted to the server 17, and the server 17 includes the signal analysis unit 11 and the determination unit 12. Moreover, the determination result of the physiological / psychological state determined by the determination unit 12 is transmitted to the communication unit 15 via the communication unit 16 and can be displayed. For example, a mobile phone is used as the communication unit 15.

  With the above configuration, when a person sits on the chair on which the main body 6 is installed, the piezoelectric sensor 2 is deformed by the movement of the person, and the piezoelectric sensor 2 outputs a voltage signal corresponding to the deformation acceleration due to the piezoelectric effect. A body movement signal synchronized with the heartbeat of the person is extracted from the output signal of the piezoelectric sensor 2 by the filter unit 51 and the amplification unit 52 of the amplifier unit 5. Then, the Lyapunov exponent is calculated by the comparison means 9 and the Lyapunov exponent calculation means 10 in the same processing flow as in the first embodiment. The calculated Lyapunov exponent is transmitted to the center server 17 via the communication means 15 and 16 as time-series data of a predetermined length.

  In the server 17, at least one of the average value and the standard deviation of the Lyapunov exponent is calculated by the signal analysis unit 11 based on the transmitted time series data of the Lyapunov exponent, and the average value and the standard deviation of the Lyapunov exponent are calculated by the determination unit 12. The physiological / psychological state is determined based on at least one of the deviations. The determination result is encrypted and stored in the memory in the server 17 in correspondence with the personal ID, and is transmitted to the communication unit 15 via the communication unit 16. The transmitted determination result can be browsed by the communication means 15. It is also possible to display the trend by accessing the memory in the server 17 from the communication means 15 at an arbitrary time, browsing the stored data corresponding to the personal ID.

  Due to the above action, there is a problem that the signal processing amount in the determination unit 8 is large in the first embodiment, the recording capacity is large, and the determination unit is large, but in this embodiment, the signal analysis means 11 and Since the determination unit 12 is built in the server side, the burden on the user side device is reduced, and the apparatus can be downsized.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the first embodiment is that the home appliance 19 and the equipment 20 installed in the living environment are controlled based on the output signals of the signal analysis means 11 and the determination means 12. This is a living system including the control means 18. Here, the control means 18 is connected to the home appliance 19 and the equipment 20 via a home LAN.

With the above configuration, the control unit 18 controls the home appliance 19 and the facility device 20 installed in the environment where the living body lives based on the output signals of the signal analysis unit 11 and the determination unit 12. In particular, the home appliance 19 and the equipment 20 are controlled so as to increase at least one of the average value and standard deviation of the Lyapunov exponent. For example, if you are tired and woke up in the morning and the standard deviation of the Lyapunov exponent is large, but the brain is not active and the average Lyapunov exponent is low, you can increase the illuminance of the luminaire or wake up from the audio device Stimulate the sensory organs, such as playing music that raises the degree, or load a simple task and control so that the activity gradually increases, so that the average Lyapunov exponent increases. Moreover, the control means 18 memorize | stores the control conditions of the household appliance 19 and the equipment 20 which become the area | region I of FIG. 20 may be controlled to be in the region I state.

  For example, in a massage chair or bathroom, the chair is equipped with an oxygen generating means that generates oxygen, or is installed in the bathroom to increase the oxygen concentration and increase the activity of the brain. A means may be provided and used to control blood flow to the head to reduce fatigue. The oxygen generating means and the neck massage control conditions when the living body is in the region I in FIG. 7 are stored in advance. When the living body is out of the region I, the oxygen generating means and the massage are stored under the stored conditions. Control the chair and promote it to be in Region I.

  Contrary to the above, when going to bed, the home electrical appliance 19 and the equipment 20 are controlled so that the average value of the Lyapunov exponent is lowered to reduce the brain activity and promote sleep onset. For example, lighting is dimmed or monotonous music is generated to lower the activity of the brain, and temperature and humidity are adjusted to promote sleep.

  Due to the above action, since the control means for controlling the home appliances and equipment installed in the living environment based on the output signals of the signal analysis means and the determination means, the optimal living environment based on the physiological and psychological state Can be controlled.

  In addition, the control means controls household appliances and equipment so as to increase at least one of the average value and the standard deviation calculated by the signal analysis means, so that the activity of the brain is increased or the fatigue level is reduced. It is possible to control the optimal living environment according to the living conditions of the living body.

  In the above embodiment, the biological signal detection means has a cushion-type main body as a sitting tool with a built-in piezoelectric sensor. However, a living body load such as a seat, a bed, a bedding, a bathtub, a floor, and a toilet seat is used. Portable devices that can be worn while being worn by a living body such as clothes, glasses, shoes, belts, and personal digital assistants, and a part of them are in indirect contact or pressure contact A configuration may be adopted in which a piezoelectric sensor is disposed in at least one of the portable devices.

  Further, as an index of the Lyapunov exponent, the biological state may be determined based on not only the average value and the standard deviation but also the temporal change rate of the Lyapunov exponent.

  By calculating the average value and standard deviation of the Lyapunov index, it is possible to estimate the degree of brain activity and the degree of fatigue of the body.For example, the degree of interest and preference for products, programs, food, interpersonal relationships, etc. There is also a possibility of usage such as evaluation.

The block diagram of the biological condition determination apparatus in the 1st Embodiment of this invention Waveform diagram of body motion signal output from amplifier 5 when a person is sitting at rest A flowchart showing the operation procedure of the comparison means 9, Lyapunov exponent calculation means 10, signal analysis means 11, determination means 12, storage means 13 and display means 14. Waveform diagram obtained by calculating and plotting the Lyapunov exponent of the subject before and after the stress test using this embodiment Characteristic diagram showing the relationship between the mean value of Lyapunov exponent and brain activity Characteristic chart showing the relationship between the standard deviation of Lyapunov exponent and the average value Characteristic diagram showing the relationship between the mean and standard deviation of Lyapunov exponents and the psychophysiological state of the body (A) Block diagram of the biological state determination device in the second embodiment of the present invention (b) Block diagram of the amplifier unit of the biological state determination device in the second embodiment of the present invention The block diagram of the biological condition determination apparatus in the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Biological signal detection means 2 Piezoelectric sensor 6 Main body 9 Comparison means 10 Lyapunov exponent operation means 11 Signal analysis means 12 Determination means

Claims (6)

Biological signal detecting means for detecting a biological signal of the living body, Lyapunov exponent calculating means for calculating the Lyapunov exponent of the biological signal data detected by the biological signal detecting means, and the average value and standard of the output signal of the Lyapunov exponent computing means A biological state determination apparatus comprising: a signal analysis unit that calculates at least one of the deviations; and a determination unit that determines a physiological and psychological state of the biological body based on an output signal of the signal analysis unit. The biological signal detection means includes a support device that can support a living body such as a seat, a bed, a bedding, a bathtub, a floor, and a toilet seat, and a portable device that can be worn or carried by a living body such as clothes, glasses, shoes, a belt, and a portable information terminal. The living body state determination apparatus according to claim 1, wherein a body motion signal that is disposed in at least one of the body and synchronizes with at least one of heartbeat and respiration of the living body as a biological signal. The biological state determination device according to claim 2, wherein the biological signal detection means includes a cable-shaped piezoelectric sensor and a sitting tool incorporating the piezoelectric sensor. Comparing means for determining whether or not the biological signal data is within a preset setting range, the Lyapunov exponent calculating means calculates a Lyapunov exponent based on a determination result of the comparing means. The biological state determination device according to any one of 3. A living system comprising control means for controlling home appliances and equipment installed in an environment where a living body lives based on the output signals of the signal analysis means and determination means according to any one of claims 1 to 4. The living system according to claim 5, wherein the control means controls the household electrical appliance and the equipment so as to increase at least one of the average value and the standard deviation calculated by the signal analysis means.

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