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

The article considers flight safety issues related to continuous monitoring of the pilot’s functional state by using control tools to track physiological health indicators. The complexity of flight work is emphasized, which is accompanied by a whole range of unfavorable factors that reduce the efficiency of performing professional duties by the pilot. The effect of general vibration on the quality (accuracy) of assessing the pilot’s physiological indicators is studied as the latter are 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 has been developed, which is the resultant of individual frequency components of corrected vibration acceleration oriented along three axes of the Cartesian coordinate system. Mathematical simulation of the effect of general vibration on the information photoplethysmographic signal has been performed. It was shown that such effect changes the frequency-time structure of the signal, generating relative errors during the assessment of the physiological indicators, such as the level of fractional blood saturation (4.16% error), heart rate (4.78% error), and respiration (3.75% error). As a result of a practical experiment aimed at analyzing the effect of general vibration on the quality of assessment of the specified physiological indicators, it was found that, compared to the declared error of a pulse oximeter (± 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 pairwise Pearson correlation, with the pairwise correlation coefficients of 0.72, 0.83, and 0.76 for the results of measuring heart rate, fractional blood saturation level, and respiratory rate, respectively. This indicates the validity of the adopted simplifications when developing the mathematical model. The obtained results can be used to develop devices for non-invasive diagnostics of the pilot’s physiological indicators directly during the flight.