The influence of the general vibration on the quality of the assessment of the pilot's physiological indicators

Abstract

The article considers flight safety issues related to continuous monitoring of the pilot's functional state by using means of monitoring physiological health indicators, which is due to the complexity of flight work, accompanied by a whole range of unfavorable factors that reduce the efficiency of professional activity. The article studies the influence of the general vibration factor on the quality (accuracy) of the assessment of the pilot's physiological indicators recorded by non-invasive diagnostic devices in transmitted light. Such indicators include heart rate, fractional blood saturation level, and respiratory rate. A mathematical model of quasi-deterministic general vibration, which is the resultant of individual frequency components of corrected vibration acceleration directed along three axes of the Cartesian coordinate system, has been developed. Mathematical modeling of the effect of general vibration on the information photoplethysmographic signal has been performed and it has been shown that the effect changes the frequency-time structure of the signal and relative errors of the estimated physiological parameters appear – the level of fractional blood saturation (4.16 %), heart rate (4.78 %) and respiration (3.75 %). As a result of a practical experiment to analyze the effect of general vibration on the quality of assessment of the specified physiological parameters, it was found that, compared to the declared error of a pulse oximeter of ±2 %, the errors in determining the heart rate, fractional blood saturation and respiration rate increased by 3.221 %; 2.483 % and 1.906 %, respectively. The results of theoretical and practical studies have a strong pair correlation according to Pearson, the pair correlation coefficients were 0.72, 0.83, 0.76 for the results of measurements of heart rate, fractional blood saturation level and respiratory rate, respectively, which indicates the validity of the adopted simplifi ations in the development of the mathematical model. The obtained results can be used to develop devices for non-invasive diagnostics of the pilot's physiological indicators, functioning directly during the flight.