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Biological state estimation device, biological state estimation system, and computer program

  • US 10,136,850 B2
  • Filed: 10/14/2010
  • Issued: 11/27/2018
  • Est. Priority Date: 10/14/2009
  • Status: Active Grant
First Claim
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1. A biological body state estimation device for estimating a state of fatigue of a person using a biological signal obtained from an upper body of the person, comprising:

  • an air pack configured to be brought into contact with a back part of the person and whose pressure has a pressure fluctuation that fluctuates with fluctuation in the aorta caused by movement of the heart, the air pack being further configured to output the pressure fluctuation as the biological signal; and

    circuitry in electronic communication with the air pack and configured toreceive the biological signal from the air pack;

    analyze the biological signal, and acquire and sort a homeostatic function level of the person at a predetermined point of time into a plurality of stages;

    plot the homeostatic function level in a time series by taking each stage of the homeostatic function level on a vertical axis and time on a lateral axis and display a fluctuation degree of the homeostatic function level on a display circuit as a graph; and

    determine the state of fatigue from the homeostatic function level;

    wherein the circuitry is configured to analyze the biological signal and acquire and sort the homeostatic function by;

    acquiring a frequency of the biological signal;

    conducting a movement calculation to acquire a slope of the frequency for each predetermined time window set with a predetermined overlapped time from the frequency of the biological signal and acquiring a time-series waveform of the slope of the frequency obtained for each time window;

    differentiating the time-series waveform of the slope of the frequency;

    integrating the time-series waveform of the slope of the frequency;

    acquiring a rectangular wave from an increase/decrease of the time-series waveform of the slope of the frequency;

    acquiring a describing function and a describing function amplitude value between the time-series waveform of the slope of the frequency in an arbitrarily set first time zone and the time-series waveform of the slope of the frequency in a second time zone after the first time zone;

    applying absolute value processing to the time-series waveform of the respective slopes of the frequency by using a time-series waveform of the frequency of the biological signal using a maximum value of the time-series waveform of the biological signal and a time-series waveform of the frequency of the biological signal using a zero-crossing point where the sign of the time-series waveform of the biological signal is switched; and

    acquiring the stage of the homeostatic function level by determining whether at least two indices indicate a characteristic change, wherein the at least two indices have the characteristic change according to said each stage of the homeostatic function level and are chosen independently for said each stage of the homeostatic function level, the at least two indices comprising at least two of the slope of the frequency, the differential value, the integral value, the sign of the rectangular wave, the describing function amplitude value, and two absolute values of the time-series waveform of the slope of the frequency.

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