Method and system for evaluating multi-modal pilot physical and mental state based on flight load

Abstract

The present application relates to a kind of multi-modal pilot physical and mental state evaluation method and system based on flight load, belong to the field of aviation medical training. Including the multi-modal physiological signal of pilot in resting state is collected and pretreated, and resting physical and mental state physiological index is extracted, and the individual resting baseline value of each pilot is calculated based on resting physical and mental state physiological index;Wherein multi-modal physiological signal includes electrocardiogram, respiratory wave, electromyogram and electroencephalogram signal;Multi-modal physiological signal of pilot after flight is collected and pretreated, and post-flight physical and mental state physiological index is extracted;Based on post-flight physical and mental state physiological index and individual resting baseline value, the multi-dimensional recovery degree of pilot after flight is calculated respectively;Based on multi-dimensional recovery degree, pilot physical and mental state evaluation result is generated;Wherein multi-dimensional recovery degree includes at least one of brain nerve state recovery degree, autonomic nerve state recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aviation medical training, and in particular to a multi-modal pilot physical and mental state evaluation method and system based on flight load. BACKGROUND

[0002] With the complexity, long duration and high intensity of modern flight tasks, pilots bear huge physical and mental load during flight. Flight tasks not only require pilots to continuously process multi-source information and maintain high attention, but also need to cope with multiple stress factors such as high-load maneuver, cabin hypoxia, vibration and noise. These loads will activate the sympathetic nervous system, suppress the parasympathetic nervous activity, cause a series of physiological changes such as increased heart rate, decreased heart rate variability, increased respiratory rate, and sustained muscle tension. If the pilot cannot recover in time after the task, fatigue accumulation may occur, which will affect the safety of subsequent flights.

[0003] Currently, the evaluation of pilot's physical and mental state after flight in the field of aviation medicine at home and abroad has the following technical limitations:

[0004] (1) Single evaluation index: existing technologies mostly rely on single indicators such as heart rate or heart rate variability (HRV), which cannot comprehensively reflect the comprehensive state of the pilot's cardiovascular system, autonomic nervous system, central nervous system, respiratory system and muscle system, and the evaluation results are one-sided, with high risk of misjudgment.

[0005] (2) Ignoring individual baseline differences: existing methods generally use group reference values or fixed thresholds, without considering the differences in individual baseline physiology (such as different resting heart rates and HRV baselines) among pilots, resulting in large individual differences in evaluation results and poor adaptability.

[0006] (3) Lack of system-level integrated evaluation model: current technologies are mostly "index stacking", without building a unified and interpretable integrated scoring system, which cannot output clear recovery levels, and is not conducive to the rapid decision-making of aviation doctors for task release. SUMMARY

[0007] In view of the above analysis, the embodiments of the present application aim to provide a multi-modal pilot physical and mental state evaluation method and system based on flight load, to solve the defects of the existing pilot physical and mental state evaluation method, such as single evaluation index, ignoring individual baseline differences, and lack of system-level integrated evaluation model, which leads to one-sided evaluation results, large individual differences and is not conducive to the decision-making of aviation doctors for task release.

[0008] The present application provides a multi-modal pilot physical and mental state evaluation method based on flight load, comprising the following steps:

[0009] The multi-modal physiological signals of the pilots in a resting state are collected and preprocessed, physiological indexes of the resting physical and mental state are calculated, and individual resting baseline values of each pilot are calculated based on the physiological indexes of the resting physical and mental state; wherein the multi-modal physiological signals include electrocardiogram, respiratory wave, electromyogram and electroencephalogram signals;

[0010] The multi-modal physiological signals of the pilots after flight are collected and preprocessed, and physiological indexes of the physical and mental state after flight are calculated;

[0011] Based on the physiological indexes of the physical and mental state after flight and the individual resting baseline values, multi-dimensional recovery degrees of the pilots after flight are calculated respectively; and the physical and mental state evaluation results of the pilots are generated based on the multi-dimensional recovery degrees; wherein the multi-dimensional recovery degrees include at least one of brain nerve state recovery degree, autonomic nerve state recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree.

[0012] Further, the individual resting baseline values include: theta wave baseline value θ rest , alpha wave baseline value α rest , beta wave baseline value β rest , heart rate baseline value HR rest , high frequency baseline value HF rest , low frequency to high frequency ratio baseline value LF / HF rest , standard deviation of RR interval baseline value SDNN rest , root mean square of adjacent interval difference baseline value RMSSD rest , low frequency baseline value LF rest , respiratory rate baseline value RR rest , average rectified electromyogram baseline value AEMG rest , and mean power frequency baseline value MPF rest .

[0013] Further, the physiological indexes of the physical and mental state after flight include heart rate HR, standard deviation of RR interval SDNN, root mean square of adjacent interval difference RMSSD, low frequency LF, high frequency HF, low frequency to high frequency ratio LF / HF, respiratory rate RR, average rectified electromyogram value AEMG, mean power frequency MPF, theta wave value, alpha wave value and beta wave value; the extraction of the physiological indexes of the physical and mental state after flight includes:

[0014] Based on the electrocardiogram signal, heart rate HR, time domain index of heart rate variability and frequency domain index are calculated; wherein the time domain index includes standard deviation of RR interval SDNN and root mean square of adjacent interval difference RMSSD, and the frequency domain index includes low frequency LF, high frequency HF and low frequency to high frequency ratio LF / HF;

[0015] Based on the respiratory wave signal, respiratory rate RR is calculated;

[0016] calculating an average rectified myoelectric value AEMG and a mean power frequency MPF based on the myoelectric signal;

[0017] calculating a theta wave value, an alpha wave value and a beta wave value based on the electroencephalogram signal.

[0018] Further, calculating a theta wave recovery efficiency θ rest based on the theta wave value and a theta wave baseline value θ n ;

[0019] calculating an alpha wave recovery efficiency α rest based on the alpha wave value and an alpha wave baseline value α n ;

[0020] calculating a beta wave recovery efficiency β rest based on the beta wave value and a beta wave baseline value β n ;

[0021] calculating a recovery degree of the brain nerve state of the pilot after the flight by weighting θ n , α n and β n .

[0022] Further, calculating a heart rate recovery efficiency HR rest based on the heart rate HR and a heart rate baseline value HR n ;

[0023] calculating a high frequency recovery efficiency HF rest based on the high frequency HF and a high frequency baseline value HF n ;

[0024] calculating a low frequency to high frequency ratio recovery efficiency LF / HF rest based on the low frequency to high frequency ratio LF / HF and a low frequency to high frequency ratio baseline value LF / HF n ;

[0025] calculating a recovery degree of the autonomic nerve state of the pilot after the flight by weighting HR n , HF n and LF / HF n .

[0026] Further, calculating a standard deviation of RR intervals recovery efficiency SDNN rest based on the standard deviation of RR intervals SDNN and a standard deviation of RR intervals baseline value SDNN n ;

[0027] calculating a recovery efficiency of the root mean square of successive differences of adjacent intervals RMSSD rest based on the root mean square of successive differences of adjacent intervals RMSSD and a root mean square of successive differences of adjacent intervals baseline value RMSSD n ;

[0028] Based on low frequency LF and low frequency baseline value LF rest , calculate low frequency recovery efficiency LF n ;

[0029] Based on SDNN n , RMSSD n and LF n , the psychological stress and stress recovery degree are calculated by weighting.

[0030] Further, based on respiratory rate RR and respiratory rate reference value RR rest , calculate the respiratory rate recovery efficiency BR n ;

[0031] Based on heart rate recovery efficiency HR n and respiratory rate recovery efficiency BR n , the cardiovascular system recovery degree is calculated by weighting.

[0032] Further, based on average rectified muscle electrical value AEMG and average rectified muscle electrical reference value AEMG rest , calculate the average rectified muscle electrical value recovery efficiency AEMG n ;

[0033] Based on average power frequency MPF and average power frequency reference value MPF rest , calculate the average power frequency recovery efficiency MPF n ;

[0034] Based on AEMG n and MPF n , the muscle state recovery degree is calculated.

[0035] Further, the rating threshold is set for the five dimensions of the brain nerve state recovery degree, the autonomic nerve state recovery degree, the psychological stress and stress recovery degree, the cardiovascular system recovery degree and the muscle state recovery degree respectively.

[0036] Based on the rating threshold, each recovery degree is divided into a plurality of recovery grades.

[0037] Based on the calculated value of each dimension, the recovery grade and the corresponding evaluation conclusion of each dimension are obtained.

[0038] According to the principle of the wooden barrel, the evaluation conclusion of the dimension with the lowest recovery grade is taken as the final pilot physical and mental state evaluation result.

[0039] The application also provides a multi-modal pilot physical and mental state evaluation system based on flight load, which comprises an individual resting baseline construction module M1, a post-flight physiological index extraction module M2 and a multi-dimensional recovery degree evaluation and result generation module M3.

[0040] The individual resting baseline modeling module M1 is used for collecting and preprocessing multi-modal physiological signals of the pilot in a resting state, extracting a resting psychosomatic state physiological index, and calculating an individual resting baseline value of each pilot based on the resting psychosomatic state physiological index; wherein the multi-modal physiological signals include electrocardiogram, respiratory wave, electromyogram and electroencephalogram signals;

[0041] The post-flight physiological index extraction module M2 is used for collecting and preprocessing multi-modal physiological signals of the pilot after flight, and extracting a post-flight psychosomatic state physiological index;

[0042] The multi-dimensional recovery degree evaluation and result generation module M3 is used for calculating a multi-dimensional recovery degree of the pilot after flight based on the post-flight psychosomatic state physiological index and the individual resting baseline value, and generating a psychosomatic state evaluation result of the pilot based on the multi-dimensional recovery degree; wherein the multi-dimensional recovery degree includes at least one of a brain nerve state recovery degree, an autonomic nerve state recovery degree, a psychological stress and stress recovery degree, a cardiovascular system recovery degree and a muscle state recovery degree.

[0043] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0044] 1. The present application innovatively integrates four types of heterogeneous physiological signals, i.e. electrocardiogram, respiratory wave, electromyogram and electroencephalogram, to comprehensively evaluate the psychosomatic state of the pilot from multiple dimensions such as cardiovascular system, autonomic nervous system, muscle system and central nervous system, overcoming the defects of the prior art that rely on a single index to lead to one-sided evaluation results and high risk of misjudgment, and being able to fully and accurately reflect the true fatigue and recovery level of the pilot. The fusion evaluation of multi-modal physiological signals is realized, and the comprehensiveness and accuracy of the evaluation are improved;

[0045] 2. The present application establishes an individual resting baseline value for each pilot, and calculates the recovery efficiency of each physiological index based on the individual resting baseline value, completely changing the extensive mode of the prior art that uses group reference values or fixed thresholds. This design fully considers the basic physiological differences between individual pilots, making the evaluation results more personalized, scientific and reliable, and effectively solving the problem of poor adaptability of existing methods. By introducing individualized resting baseline, the individual adaptability and accuracy of the evaluation are significantly enhanced;

[0046] 3. The present application constructs recovery degree models of five dimensions, i.e. brain nerve state, autonomic nerve state, psychological stress and stress, cardiovascular system and muscle state, and finally generates a unified and hierarchical evaluation conclusion based on the "bucket principle", solving the problem of simply stacking physiological indexes in the prior art. This provides clear and intuitive task release decision basis for aviation doctors, solves the pain points of the prior art that lack system integration and are difficult to be directly used for flight decision, and improves the decision efficiency of aviation safety management;

[0047] 4、The application first introduces the flight time of the pilot as a weighting factor into the calculation of the heart rate and heart rate variability recovery degree, fills the blank of the traditional evaluation ignoring the cumulative effect of stress residues, and provides quantitative support for flight safety and health management.

[0048] In the application, the above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent specification, and some advantages will become apparent from the specification or be understood by implementing the application. The purposes and other advantages of the application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0049] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and serve to explain the principles of the application, but are not intended to limit the scope of the application. In the drawings, the same reference symbols refer to the same components.

[0050] Figure 1 A flow chart of a multi-modal pilot physical and mental state evaluation method based on flight load in an embodiment of the application;

[0051] Figure 2 A multi-dimensional recovery radar chart after flight in an embodiment of the application;

[0052] Figure 3 A module schematic diagram of a multi-modal pilot physical and mental state evaluation system based on flight load in an embodiment of the application. DETAILED DESCRIPTION

[0053] The preferred embodiments of the application will be described in detail below with reference to the accompanying drawings, wherein the drawings constitute a part of this specification and are used to explain the principles of the embodiments of the application, but are not intended to limit the scope of the application.

[0054] One specific embodiment of the application discloses a multi-modal pilot physical and mental state evaluation method based on flight load, as shown in Figure 1 The method comprises the following steps:

[0055] Step S1, collecting multi-modal physiological signals of the pilot in a resting state and pre-processing, calculating resting physical and mental state physiological indicators, and calculating individual resting baseline values of each pilot based on the resting physical and mental state physiological indicators; wherein the multi-modal physiological signals include electrocardiogram, respiration wave, electromyogram and electroencephalogram signals;

[0056] Step S2, collecting multi-modal physiological signals of the pilot after flight and pre-processing, and calculating post-flight physical and mental state physiological indicators;

[0057] Step S3, based on the flight post-physical and mental state physiological indicators and individual resting baseline values, respectively calculating the multi-dimensional recovery degree of the pilot after flight; based on the multi-dimensional recovery degree, generating the pilot's physical and mental state evaluation results; wherein the multi-dimensional recovery degree includes at least one of brain nerve state recovery degree, autonomic nerve state recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree.

[0058] Step S1, comprising steps S11-S13.

[0059] Step S11, collecting multi-modal physiological signals of the pilot in a resting state and pre-processing.

[0060] Pre-flight baseline data collection, in the calm state of the pilot's physical and mental state, the multi-modal physiological signals of the pilot in the resting state are collected, including electrocardiogram ECG (Electrocardiogram), respiration wave signal RESP (Respiration), electromyogram EMG (Electromyography) and electroencephalogram EEG (Electroencephalogram) data.

[0061] Electrocardiogram ECG for recording heart electrical activity; respiration wave signal RESP for reflecting the breathing process; electromyogram EMG for recording muscle electrical activity; electroencephalogram EEG for recording brain electrical activity.

[0062] Exemplarily, the resting state data collection duration is 20 minutes; in actual application, the collection duration can be set according to specific needs.

[0063] For establishing the individualized resting baseline value of the pilot, the individual baseline of each pilot is obtained.

[0064] Based on the electrocardiograph, the electrocardiogram ECG and respiration wave signal RESP data of the pilot are obtained; the sampling frequency of the electrocardiogram ECG is 100Hz, and the sampling frequency of the respiration wave signal RESP is 25Hz;

[0065] Based on the electromyography collection device, the electromyography EMG data of the pilot is obtained, and the sampling frequency of the electromyography EMG is 512Hz.

[0066] Based on the electroencephalogram collection device, the electroencephalogram data of the pilot is collected, and the sampling frequency of the electroencephalogram EEG is 256Hz.

[0067] The multi-modal physiological signals in the resting state are pre-processed, including:

[0068] Filtering (e.g. band-pass filtering to remove noise), artifact rejection, missing value imputation, and improving signal-to-noise ratio are performed to ensure data quality and accuracy of subsequent analysis.

[0069] Artifact rejection: moving window standard deviation method is used to detect and reject abnormal segments (e.g. body motion artifacts).

[0070] Missing value imputation: linear interpolation or adjacent period mean is used to fill in missing values.

[0071] Step S12: Based on the pre-processed multi-modal physiological signals, calculate the physiological indicators of the resting mind-body state.

[0072] (1) For ECG signals, calculate heart rate HR (Heart Rate) based on the pre-processed ECG signals ECG in resting state, calculate time-domain indicators of heart rate variability, including: standard deviation of NN intervals SDNN (Standard Deviation of NN intervals), root mean square of successive differences RMSSD (Root Mean Square of Successive Differences); calculate frequency-domain indicators, including: low frequency LF (Low Frequency), high frequency HF (High Frequency), low-to-high frequency ratio LF / HF (Low Frequency / High Frequency ratio).

[0073] Heart rate HR is calculated as follows:

[0074]

[0075] where RR mean is the average of all RR intervals of the collected ECG signals in resting state, RR interval is the time interval between two consecutive heartbeats (heartbeats), usually in milliseconds (ms), and is a key indicator in ECG signal analysis.

[0076] The standard deviation of RR intervals SDNN is the standard deviation of all normal sinus RR intervals, reflecting the overall fluctuation of heart rate variability HRV (Heart Rate Variability). SDNN is calculated as follows:

[0077]

[0078] where M is the total number of RR intervals of the collected ECG signals in resting state, RR i is the i-th RR interval, and RR mean is the average of all RR intervals.

[0079] Root Mean Square of Successive Differences (RMSSD), is the root mean square of the differences between adjacent NN (Normal-to-Normal Intervals) intervals, reflecting short-term heart rate variability (HRV) fluctuations. RMSSD is calculated as follows:

[0080]

[0081] where RR i+1 and RR i are two adjacent RR intervals.

[0082] Low Frequency (LF), is calculated as follows:

[0083]

[0084] High Frequency (HF), is calculated as follows:

[0085]

[0086] where PSD(f) is the Power Spectral Density function of the ECG signal, representing the power of the ECG signal at frequency f.

[0087] Low Frequency / High Frequency ratio (LF / HF), is calculated as follows:

[0088]

[0089] (2) Calculate the respiratory rate based on the respiratory wave signal.

[0090] Respiratory Rate (RR), is calculated as follows:

[0091]

[0092] where N is the number of complete respiratory cycles of the respiratory wave signal identified within the time window T (usually determined by counting the number of peaks or troughs); T is the time length of the analysis window; 60 is used to convert "times / second" to "times / minute".

[0093] (3) Based on the electromyographic signal, calculate the average rectified electromyographic value and the average power frequency.

[0094] Based on the pre-processed EMG, the average rectified EMG (AEMG) and the mean power frequency (MPF) are calculated.

[0095] The average rectified EMG (AEMG) is calculated as follows:

[0096]

[0097] Where x(t) is the pre-processed surface EMG signal, T is the analysis time window, usually 0.1-1 second, and [t0, t0+T] is the time point range within the window.

[0098] |x(t)| takes the absolute value of the pre-processed signal, eliminating the negative component to obtain the rectified signal.

[0099] The mean power frequency (MPF) needs to be converted from the time domain signal to the frequency domain signal through Fourier transform, and then calculated based on the power spectrum.

[0100] First, the pre-processed EMG signal is converted from each time domain signal to a frequency domain signal through fast Fourier transform to obtain the amplitude spectrum. The power spectrum reflects the power ratio of different frequency components, which is calculated as follows:

[0101]

[0102] Where x(f) is the amplitude spectrum after FFT (Fast Fourier Transform), and f is the sampling frequency of the EMG signal.

[0103] MPF is the weighted average of the power spectrum, with the weight being the power of each frequency, which is calculated as follows:

[0104]

[0105] Where f low and f high are the effective frequency range, the numerator is the power-weighted frequency sum, and the denominator is the total power.

[0106] (4) Calculate the theta wave value, alpha wave value and beta wave value based on the EEG signal.

[0107] Calculate the theta wave, alpha wave and beta wave values based on the pre-processed EEG signal.

[0108] The pre-processed EEG signal EEG contains power frequency interference and needs to be filtered and detrended. The time domain signal x filtered(t) represents the convolution of the preprocessed EEG signal with the filter coefficients h(k), as shown below:

[0109]

[0110] Where M is the filter order.

[0111] Subtracting (a(tk)+b) from the preprocessed EEG signal x(tk) is the detrending process, where a is the slope and b is the intercept, to eliminate slow drift in the signal.

[0112] Time domain signal x filtered (t) is converted into a frequency domain signal to obtain the complex amplitude at each frequency point, as shown below:

[0113]

[0114] Based on the frequency ranges of theta, alpha, and beta waves, calculate the frequency band power of each wave, as the theta wave value, alpha wave value, and beta wave value, as follows:

[0115]

[0116] Step S13: Calculate the individual resting baseline value for each pilot based on the physiological indicators of resting physical and mental state.

[0117] The individual resting baseline value includes: the theta wave baseline value θ. rest α wave baseline value α rest β wave baseline value β rest Heart rate baseline value HR rest High-frequency baseline value (HF) rest Low-frequency to high-frequency ratio baseline value LF / HF rest RR interval standard deviation baseline value SDNN rest Root mean square base value of the difference between adjacent periods (RMSSD) rest Low-frequency baseline value LF rest Respiratory rate baseline (RR) rest Average rectified electromyography (AEMG) reference value rest and average power frequency reference value MPF rest .

[0118] The average value of each pilot's resting physical and mental state physiological indicators is taken to obtain the corresponding baseline value.

[0119] For example: the baseline value of the theta wave θ rest α wave baseline value α rest β wave baseline value β rest The mean values ​​were obtained based on the theta wave, alpha wave, and beta wave values, which are physiological indicators of the pilot's resting physical and mental state.

[0120] The purpose of step S1 is to establish individualized baseline for the evaluation of the physical and mental state recovery of the pilot after flight. This step calculates the individual resting baseline value of each pilot by collecting the multi-modal physiological signals (ECG, respiratory wave, EMG, and EEG) of the pilot in the resting state, and pre-processing and feature extraction of these signals. These baseline values cover the resting state levels of multiple physiological indicators such as heart rate, heart rate variability, respiratory rate, muscle activity, and brain activity, providing personalized baseline standards for subsequent comparison and recovery evaluation of post-flight data.

[0121] Step S2, specifically.

[0122] Post-flight data collection for each pilot starts immediately after each pilot finishes flying; the purpose is to capture the complete dynamic process of the pilot from the peak of stress to the recovery of steady state; exemplarily, the collection duration is 1 hour;

[0123] EGG, RESP, EMG, EEG are collected at their respective sampling frequencies with the multi-modal physiological signals collected in the resting state; the pre-processing process is the same as that of the multi-modal physiological signals in the resting state; this will not be repeated here.

[0124] The post-flight physical and mental state physiological indicators include heart rate HR, standard deviation of RR interval SDNN, root mean square of adjacent interval difference RMSSD, low frequency LF, high frequency HF, low frequency to high frequency ratio LF / HF, respiratory rate RR, average rectified electromyogram value AEMG, mean power frequency MPF, theta wave value, alpha wave value, and beta wave value; the extraction of the post-flight physical and mental state physiological indicators includes:

[0125] Calculate heart rate HR, heart rate variability time domain indicators, and frequency domain indicators based on the ECG signal; wherein the time domain indicators include standard deviation of RR interval SDNN and root mean square of adjacent interval difference RMSSD, and the frequency domain indicators include low frequency LF, high frequency HF, and low frequency to high frequency ratio LF / HF;

[0126] Calculate respiratory rate RR based on the respiratory wave signal;

[0127] Calculate average rectified electromyogram value AEMG and mean power frequency MPF based on the EMG signal;

[0128] Calculate theta wave value, alpha wave value, and beta wave value based on the EEG signal.

[0129] The calculation of the post-flight physical and mental state physiological indicators of each pilot is the same as the calculation of the resting physical and mental state physiological indicators of each pilot, which will not be repeated here.

[0130] The step S2 is to collect the multi-modal physiological signals of the pilot after the flight, calculate and extract the physical and mental state physiological indexes after pre-processing, dynamically track the whole process of the pilot from the stress state to the recovery steady state, and provide a data basis for obtaining the evaluation results of the physical and mental state of the pilot.

[0131] The step S3 is specifically.

[0132] Based on the recovery rate of the indexes such as HR, RR, SDNN, RMSSD, LF, HF, LF / HF, AMEG, MPH, theta wave value, alpha wave value, beta wave value, etc. to the resting state after the flight, the recovery ability of the pilot is quantified.

[0133] Based on the electrocardiogram, respiration wave, electromyogram and electroencephalogram signals collected after each pilot's flight, the recovery state of the physical and mental state of the pilot after the flight is evaluated.

[0134] Among them, the physical state mainly evaluates the cardiovascular recovery speed and muscle state recovery speed;

[0135] The mental state mainly evaluates the brain state recovery speed, autonomic nerve recovery speed and psychological stress and stress recovery speed.

[0136] The multi-dimensional recovery degree includes at least one of the brain nerve state recovery degree, the autonomic nerve state recovery degree, the psychological stress and stress recovery degree, the cardiovascular system recovery degree and the muscle state recovery degree.

[0137] The brain nerve state recovery speed is related to the theta wave value, the alpha wave value and the beta wave value;

[0138] The autonomic nerve state recovery speed is related to HR, HF and LF / HF;

[0139] The psychological stress and stress recovery speed is related to SDNN, RMSSD and LF;

[0140] The cardiovascular system recovery speed is related to HR and RR;

[0141] The muscle state recovery speed is related to AMEG and MPH.

[0142] (1) Calculate the brain nerve state recovery degree.

[0143] Based on the theta wave value and the theta wave baseline value θ rest , calculate the theta wave recovery efficiency θ n ;

[0144] Based on the alpha wave value and the alpha wave baseline value α rest , calculate the alpha wave recovery efficiency α n ;

[0145] Based on the beta wave value and the beta wave baseline value β rest, the recovery efficiency of beta wave β n ;

[0146] Based on θ n , α n and β n , the recovery degree of the pilot's brain nerve state after flight is calculated by weighting.

[0147] The recovery degree of the brain nerve state directly quantifies the degree of recovery of the pilot's central nervous system from task load after flight, and further reveals the current central nervous fatigue level and the remaining cognitive function reserve. The recovery degree of the brain nerve state is based on the evaluation of the excitability, inhibition, cognitive load and psychological state of the central nervous system based on the EEG data.

[0148] The recovery degree of the brain nerve state reflects the overall recovery degree by quantifying the recovery degree of each EEG frequency band power value relative to the individual resting baseline level after exercise.

[0149] ①Calculate the recovery efficiency of θ wave θ n

[0150] The recovery efficiency of θ wave θ n , refers to the speed and degree of the brain's θ rhythm activity returning from a high level state representing fatigue to the resting baseline level after the task is completed. θ n is a quantitative value for objectively comparing the recovery of different individuals or the same individual after different task loads.

[0151] The power of θ wave (4-8Hz) is mainly in the frontal lobe and central area, and the abnormal increase in power is highly related to mental burnout, sleepiness and cognitive fatigue.

[0152] The recovery efficiency of θ wave θ n is calculated as follows:

[0153]

[0154] Where, θ rest is the size of the pilot's θ value in the state of no flight stress and complete body relaxation, which is the baseline value within 20 minutes; θ t0 is the size of the instant θ value after the flight ends, reflecting the peak residual level of flight stress; θ tn is the size of the θ value after n minutes of flight; θ n is the recovery rate of θ wave after n minutes of flight. Usually n is 5 minutes.

[0155] The closer θ n is to 100%, the closer the recovery of θ wave is to the resting state, and the stronger the brain nerve regulation ability is.

[0156] ②Calculate the recovery efficiency of α wave α n

[0157] alpha wave recovery efficiency α n This refers to a key indicator for assessing the brain's relaxation function and recovery from a resting state. It directly reflects the brain's ability to switch from a highly excited, focused task mode back to a calm, relaxed baseline state.

[0158] Alpha wave (8-13Hz) power: mainly in the occipital lobe. Increased power indicates a relaxed state, and the rebound of alpha power after exercise is a sign of mental relaxation.

[0159] The alpha wave recovery efficiency is calculated as follows:

[0160]

[0161] Where, α rest The α value represents the pilot's value under conditions of no flight stress and complete physical relaxation, and is the baseline value over 20 minutes; α t0 The immediate α value after the end of flight reflects the peak residual level of flight stress; α tn Let α be the value of α n minutes after the end of the flight; α n Let be the alpha wave recovery rate n minutes after the end of the flight. For example, n is 5 minutes.

[0162] α n The closer it is to 100%, the closer the alpha wave recovery is to the resting state, and the stronger the brain's neural regulation ability.

[0163] ③ Calculate the β-wave recovery efficiency β n

[0164] β wave recovery efficiency β n It refers to a key indicator that measures the speed and extent of the recovery of the cerebral cortex function, especially alertness, attention regulation, and neurometabolic state, from exercise stress.

[0165] Beta wave (13-30Hz) power: Excessive power indicates that the brain is still in a state of high excitement, alertness or anxiety.

[0166] The alpha wave recovery efficiency is calculated as follows:

[0167]

[0168] Where, β rest The β value represents the pilot's value in a state of complete relaxation without flight stress, and is the baseline value over 20 minutes; β t0 The immediate β value after the end of flight reflects the peak residual level of flight stress; β tn Let β be the value of β n minutes after the end of the flight; β nThe recovery rate of beta waves n minutes after the flight. Usually n is 5 min.

[0169] β n The closer to 100%, the closer the beta wave recovery to the resting state, the stronger the brain nerve regulation ability.

[0170] ④ Based on θ n , α n and β n , the brain nerve state recovery degree of the pilot after the flight is calculated by weighting.

[0171] The evaluation of the brain nerve state recovery degree is calculated by weighting and integrating the recovery rates of the above indexes. For example, θ n directly reflects mental fatigue, with the highest sensitivity, and the weight is set to 40%; α n reflects the degree of physical and mental relaxation, and the weight is set to 30%; β n directly reflects the degree of brain excitement or stress, and the weight is set to 30%. The calculation formula is as follows:

[0172] BAS t = 0.4 × θ n + 0.3 × α n + 0.3 × β n Formula (17)

[0173] The weights of θ n , α n and β n may be changed according to specific needs in specific applications.

[0174] BAS t ≥ 80%, indicating complete recovery, and the next flight task can be normally executed;

[0175] 60% ≤ BAS t < 80%, indicating partial recovery, and the rest time needs to be extended, and whether to execute the task is decided after evaluation;

[0176] BAS t < 60%, indicating insufficient recovery, and the flight task needs to be suspended for further rest. As follows:

[0177]

[0178] The threshold values of BAS t 80%, 60% can be changed according to specific needs in specific applications.

[0179] (2) Calculate the autonomic nerve state recovery degree

[0180] Based on heart rate HR and heart rate baseline value HRrest Calculate heart rate recovery efficiency HR n ;

[0181] Calculate high frequency HF recovery efficiency HF based on high frequency HF and high frequency baseline value HF rest n ;

[0182] Calculate low frequency high frequency ratio recovery efficiency LF / HF based on low frequency high frequency ratio LF / HF and low frequency high frequency ratio baseline value LF / HF rest n ;

[0183] Calculate the autonomic nervous state recovery degree of the pilot after flight based on HR n , HF n and LF / HF n .

[0184] The autonomic nervous state recovery degree refers to the degree and efficiency of the recovery of the autonomic nervous function of the pilot from the imbalance state in flight to the ground resting steady state after completing the flight task, which is the core physiological index for evaluating the recovery ability of the physiological function of the pilot and the adaptability of subsequent flight tasks. The higher the recovery degree, the faster the balance of the autonomic nervous state, the more sufficient the fatigue relief, and the lower the safety risk of performing the flight task again.

[0185] The evaluation of the autonomic nervous state recovery degree is based on the heart rate recovery efficiency as a speed index and the heart rate variability as a balance index, and the recovery process is judged by quantifying the ratio of the actual recovery value of the index after stress to the theoretical maximum recoverable value.

[0186] ①Calculate HR recovery efficiency HR n

[0187] HR recovery efficiency HR n reflects the speed of the heart rate of the pilot after flight from the peak value to the resting level.

[0188] During the flight task, the pilot needs to process multi-source information, maintain the stability of the flight posture, and perform maneuvering actions, and these stimuli will activate the sympathetic nerve and inhibit the parasympathetic nerve, and the heart rate will be significantly higher than the resting level; after the flight ends, the external stress stimulus weakens, and the autonomic nervous system will recover, and the parasympathetic nerve activity gradually rises, inhibiting the excessive excitement of the sympathetic nerve.

[0189] After the flight of the pilot, the body needs to quickly adjust from the stress state to the resting state, and the heart rate recovery efficiency is the core index for evaluating the autonomic nervous regulation ability and the recovery efficiency after exercise.

[0190] The formula for calculating the heart rate recovery efficiency is as follows:

[0191] ​​

[0192] wherein HR rest is the average heart rate of the pilot in the state of no flight stress and complete physical relaxation, which is the baseline value within 20 minutes, reflecting the basic balance level of the autonomic nervous system; HR t0 is the instantaneous heart rate after the flight, reflecting the peak residual level of flight stress; HR tn is the heart rate n minutes after the flight, reflecting the recovery process; HR n is the heart rate recovery rate n minutes after the flight; T is the flight duration. W(t) is the flight duration weighting term. The longer the flight duration, the smaller the HR n , representing the greater the difficulty of heart rate recovery.

[0193] HR n closer to 100%, indicating that the heart rate recovery is closer to the resting state, and the autonomic nervous regulation ability is stronger; if n = 1 min, HR n > 50%, it is generally considered that the recovery is good; if n = 5 min, HR n > 80%, it is generally considered that the recovery is good.

[0194] The flight duration weighting term W(t) is calculated as follows:

[0195]

[0196] For long flight (T≥4h), the flight duration accumulates the autonomic nervous stress load. The traditional evaluation method based on the heart rate difference at a time point, that is, the method of comparing the difference between the baseline heart rate before flight and the instantaneous heart rate during flight / post-flight to judge the stress degree, when facing the scene of longer flight duration, the difficulty of autonomic nervous recovery becomes greater. The evaluation method based on the heart rate difference at a time point only reflects the instantaneous intensity of stress, but does not associate the time span of stress effect, resulting in errors in the evaluation of recovery difficulty. Therefore, the flight duration T is introduced as a weighting factor to balance the autonomic nervous stress residue.

[0197] When T>4h, the autonomic nervous stress residue accumulates linearly; when 4h<T≤8h, the autonomic nervous stress residue changes from “linear accumulation” to “nonlinear accelerated accumulation”. The longer the flight duration, the higher the difficulty of autonomic nervous recovery.

[0198] ②Calculate the HF recovery efficiency HF n

[0199] HF recovery efficiency HF n reflects the speed of the pilot's HF recovery to the resting level after flight.

[0200] HF is the core index to measure the speed of vagus nerve function recovery of the autonomous nervous system after flight, and quantify the recovery ability of the body from flight stress. By tracking the regression process of HF value to baseline level after flight, the recovery of vagus nerve relaxation regulation function is directly reflected, and the fatigue degree of pilots can be judged.

[0201] Flight triggers the body's stress response, directly leading to a decrease in HF value; after the flight ends, the stress source disappears, and the body starts the autonomous nerve recovery mechanism, and the vagus nerve activity gradually rises, and the HF value approaches the baseline. HF n The calculation is as follows:

[0202]

[0203] HF rest is the average HF baseline value of the pilot in the state of no flight stress and complete body relaxation, which is the baseline data within 20 minutes; HF t0 is the instantaneous measured value of HF after the flight ends; HF tn is the measured value of HF n minutes after the flight ends, reflecting the recovery process; HF n is the HF recovery efficiency n minutes after exercise. Usually n is 5 minutes. W(t) is the flight length weighting term. The longer the flight length, the smaller the HF n , which represents the greater the difficulty of heart rate variability recovery.

[0204] HF n The closer to 100%, the closer the HF recovery to the resting state, the recovery of the autonomous nerve regulation to normal, and the lower the fatigue degree.

[0205] ③Calculate the LF / HF recovery efficiency LF / HF n

[0206] LF / HF recovery efficiency LF / HF n , reflecting the speed of the pilot's LF / HF recovery to the resting level after flight.

[0207] LF / HF is a key index to evaluate the balance between sympathetic and parasympathetic nerves, and its recovery efficiency is used to quantify the speed and degree of the autonomous nerve from the imbalance state to the steady state after flight.

[0208] The formula is as follows:

[0209]

[0210] LF / HF rest is the average LF / HF baseline value of the pilot in the state of no flight stress and complete body relaxation, which is the baseline data within 20 minutes; LF / HF t0 is the instantaneous measured value of LF / HF after the flight ends; LF / HFtn is the measured value of LF / HF n minutes after flight, reflecting the recovery process; LF / HF n is the recovery efficiency of LF / HF n minutes after exercise. Usually n is 5 min. W(t) is the flight duration weighting term. The longer the flight duration, the smaller the LF / HF n , indicating that the recovery of heart rate variability is more difficult.

[0211] LF / HF n is closer to 100%, indicating that the recovery of LF / HF is closer to the resting state.

[0212] ④Based on HR n , HF n and LF / HF n , the weighted calculation of the recovery degree of the autonomic nervous state ANSR t of the pilot after flight.

[0213] The evaluation of the autonomic nervous state recovery degree is calculated by weighting and integrating the recovery rates of the above indexes. Among them, HF directly reflects the vagus nerve activity and has the highest sensitivity, with a weight of 40%; LF is the core of stress activation, with a weight of 30%; HR directly reflects the rebound ability of the parasympathetic nerve, with a weight of 30%. ANSR t is calculated as follows:

[0214] ANSR t = 0.4 x HF n + 0.3 x LF / HF n + 0.3 x HR n Equation (23)

[0215] For the weights of HR n , HF n and LF / HF n , they can be changed according to specific needs in specific applications.

[0216] ANSB t ≥ 80%, indicating good recovery, the autonomic nervous system is close to the resting state, and can normally participate in subsequent flight tasks;

[0217] 60% ≤ ANSB t < 80%, indicating general recovery, and the ground rest time needs to be extended;

[0218] ANSB t < 60%, indicating insufficient recovery, indicating that there is obvious physiological fatigue, and subsequent flight tasks need to be suspended. As follows:

[0219]

[0220] For ANSBt Threshold 80%, 60%, in specific applications, can be changed according to specific needs.

[0221] (3) Calculate the psychological stress and stress recovery degree

[0222] Based on the standard deviation of RR interval SDNN and the standard deviation of RR interval baseline value SDNN rest , calculate the SDNN recovery efficiency SDNN n ;

[0223] Based on the root mean square of adjacent interval difference RMSSD and the root mean square of adjacent interval difference baseline value RMSSD rest , calculate the RMSSD recovery efficiency RMSSD n ;

[0224] Based on the low frequency LF and the low frequency baseline value LF rest , calculate the low frequency recovery efficiency LF n ;

[0225] Based on SDNN n , RMSSD n and LF n , weighted calculation to get the recovery degree of psychological stress and stress state.

[0226] The recovery degree of psychological stress and stress is an index to measure the degree of recovery of the pilot's psychological stress and mental state from flight stress to baseline level after completing the flight task.

[0227] The recovery degree of psychological stress and stress directly reflects the influence of flight stress on the physiological state of pilots and the self-regulation ability of the body: the higher the recovery degree, the faster the pilot recovers from stress, and the closer the physiological function to the normal state, which can reduce the risk and operation error probability in subsequent flight tasks; The lower the recovery degree, the more significant the residual effect of stress, and the potential threat of fatigue accumulation to flight safety should be warned.

[0228] The recovery degree of psychological stress and stress quantifies the core indicators of heart rate variability SDNN, RMSSD and LF, which together build an objective physiological evaluation system for stress and recovery from three dimensions of overall autonomic nervous regulation ability, parasympathetic nerve activity, and sympathetic-parasympathetic balance bias, suitable for dynamic monitoring scenarios after pilots fly. The recovery process is judged by the ratio of the actual recovery value of the index after stress to the theoretical maximum recoverable value.

[0229] ①Calculate the SDNN recovery efficiency SDNN n

[0230] SDNN recovery efficiency SDNN n , reflects the speed of SDNN recovery to resting level after flight.

[0231] During flight, sympathetic nerve is excited to support rapid decision and operation, and parasympathetic nerve is inhibited; when sympathetic nerve is dominant, SDNN decreases, and when parasympathetic nerve is dominant, SDNN increases, and SDNN during flight is usually lower than the resting level on the ground; after flight, the excitability of sympathetic nerve gradually decreases, and the function of parasympathetic nerve is activated from the inhibited state, and SDNN returns to the resting level.

[0232] The faster the recovery speed of SDNN and the higher the recovery degree, the better the flexibility of the autonomic nervous system of the pilot, and the higher the fatigue elimination efficiency after flight. SDNN is an important indicator reflecting the overall regulation activity of the autonomic nerve, stress and stress level, and fatigue level.

[0233] The recovery rate of SDNN, that is, the percentage of the recovered SDNN increment at a certain recovery time point to the total required recovery SDNN increment, can be used for comparison of recovery efficiency between different pilots. SDNN n The calculation is as follows:

[0234]

[0235] SDNN rest is the average SDNN reference value of the pilot in the state of no flight stress and complete body relaxation, which is the baseline data within 20 minutes; SDNN t0 is the instantaneous measured value of SDNN after flight; SDNN tn is the measured value of SDNN after flight for n minutes, reflecting the recovery process; SDNN n is the SDNN recovery efficiency after n minutes of exercise. Usually n is 5 minutes. W(t) is the flight time weighting term. The longer the flight time, the smaller the SDNN n , which represents the greater the difficulty of recovery of heart rate variability.

[0236] SDNN n The closer to 100%, the closer the recovery of SDNN to the resting state, and the recovery of autonomic nerve regulation to normal.

[0237] ②Calculate the recovery efficiency of RMSSD RMSSD n

[0238] RMSSD recovery efficiency RMSSD n , reflecting the speed of recovery of RMSSD of the pilot to the resting level after flight.

[0239] During flight, pilots need to deal with multiple high-load tasks at the same time, which can trigger the body's stress response, directly inhibiting RMSSD; after the flight, the stress source disappears, and the body starts the recovery mechanism, and the autonomic nervous system gradually rebuilds balance, and RMSSD rises.

[0240] RMSSD recovery efficiency is one of the core indicators for evaluating the cardiovascular system, autonomic nervous regulation function, flight task fatigue degree, and body recovery ability of pilots. The essence is to track the regression process of RMSSD value to the baseline level after flight, and quantify the recovery efficiency of autonomic nervous system from stress state to steady state.

[0241] RMSSD recovery rate, that is, the difference between the value after recovery and the immediate value accounts for the percentage of the difference between the baseline and the immediate value, which eliminates the individual resting RMSSD difference and can be used for comparison of recovery efficiency between different pilots.

[0242] RMSSD n , calculated as follows:

[0243]

[0244] RMSSD rest is the average RMSSD baseline value of the pilot in the state of no flight stress and complete body relaxation, which is the baseline data within 20 minutes; RMSSD t0 is the immediate measured value of RMSSD after the flight ends; RMSSD tn is the measured value of RMSSD n minutes after the flight ends, reflecting the recovery process; RMSSD n is the RMSSD recovery efficiency n minutes after exercise. Usually n is 5 minutes. The longer the flight duration, the smaller the RMSSD n , which represents the greater difficulty of heart rate variability recovery.

[0245] RMSSD n closer to 100%, indicating that the RMSSD recovery is closer to the resting state, the autonomic nervous regulation returns to normal, and the fatigue degree is low.

[0246] ③Calculate LF recovery efficiency LF n

[0247] LF recovery efficiency LF n reflects the speed of LF recovery to the resting level of the pilot after flight.

[0248] During flight, pilots need to deal with multiple high-load tasks, which can trigger the body's stress response, directly leading to the increase of LF; after the flight, the stress source disappears, and the LF value falls back to the baseline.

[0249] LF recovery efficiency is a key index to quantify the autonomic nervous system balance, cardiovascular regulation function repair efficiency after flight stress.

[0250] The formula is:

[0251]

[0252] LF rest is the average LF baseline value of the pilot in the state of no flight stress and complete body relaxation, which is the baseline value within 20 minutes; LF t0 is the instantaneous measured value of LF after the flight; LF tn is the measured value of LF n minutes after the flight, reflecting the recovery process; LF n is the LF recovery efficiency n minutes after the exercise. Usually n is 5 minutes. The longer the flight duration, the smaller the LF n , which represents the greater difficulty of heart rate variability recovery.

[0253] LF n is closer to 100%, indicating that the LF recovery is closer to the resting state, the autonomic nervous regulation returns to normal, and the fatigue level is low.

[0254] ④ Based on SDNN n , RMSSD n and LF n , the psychological stress and stress state recovery degree SR t is calculated by weighting.

[0255] The evaluation of the psychological stress and stress state recovery degree is calculated by weighting and integrating the recovery rates of the above indexes. Among them, SDNN reflects the total regulation of the autonomic nervous system, with a weight of 45%; RMSSD reflects the vagus nerve activity, with a weight of 35%; and LF reflects the sympathetic-parasympathetic balance bias, with a weight of 20%. The calculation formula is as follows:

[0256] SR t = 0.45 × SDNN n + 0.35 × RMSSD n + 0.2 × LF n Formula (28)

[0257] For the weights of SDNN n , RMSSD n and LF n , they can be changed according to specific needs in specific applications.

[0258] SR t ≥ 80% indicates good recovery, close to the baseline of physiological state, and suitable for subsequent tasks;

[0259] 50%≤ SR t <80%, indicating general recovery, not recommended to perform high-intensity flight in a short time;

[0260] SR t <50%, indicating insufficient recovery, significant stress remains, forced rest is required to avoid flight tasks. t The calculation is as follows:

[0261]

[0262] For SR t Threshold values of 80% and 50% can be changed according to specific needs in specific applications.

[0263] (4) Calculate the cardiovascular recovery degree

[0264] Based on the respiratory rate RR and the respiratory rate reference value RR rest , calculate the respiratory rate recovery efficiency BR n ;

[0265] Based on the heart rate recovery efficiency HR n and the respiratory rate recovery efficiency BR n , the cardiovascular recovery degree is calculated by weighting.

[0266] The cardiovascular recovery degree assesses the body's ability to return to a resting steady state from a stressed state. The cardiovascular system undergoes adaptive changes when pilots perform flight tasks and high-intensity maneuvers: heart rate and respiratory rate increase. When the stress ends, the system gradually recovers to the pre-stress resting baseline through regulation. The essence of judging heart rate and respiratory rate is that HR / RR will increase during stress to meet the body's metabolic needs, and during recovery, both should gradually return to the individual baseline level, and the speed, amplitude, and stability of the decline directly reflect the recovery efficiency.

[0267] The cardiovascular recovery degree is determined by quantifying the ratio of the actual recovery value of the index after stress to the theoretical maximum recoverable value to judge the recovery process.

[0268] ① Calculate the HR recovery efficiency HR n

[0269] HR recovery efficiency HR n reflects the speed at which the pilot's heart rate falls from the peak to the resting level after flight.

[0270] During flight tasks, pilots need to process multiple sources of information, maintain stable flight posture, and perform maneuvering actions. These stimuli will activate the sympathetic nerve and suppress the parasympathetic nerve, causing the heart rate to be significantly higher than the resting level. After the flight ends, the external stress stimulus weakens, and the autonomic nervous system recovers, with the parasympathetic nerve activity gradually rising and suppressing the excessive excitement of the sympathetic nerve.

[0271] After flight, the pilot's body needs to quickly adjust from the stress state to the resting state, and the heart rate recovery efficiency is the core index to evaluate the autonomic nerve regulation ability and the recovery efficiency after exercise.

[0272] The heart rate recovery efficiency is calculated as follows:

[0273]

[0274] Wherein, HR rest is the average heart rate of the pilot in the state of no flight stress and complete body relaxation, which is the baseline value within 20 minutes, reflecting the basic balance level of the autonomic nerve; HR t0 is the instantaneous heart rate after the flight, reflecting the peak residual level of flight stress; HR tn is the heart rate after n minutes after the flight, reflecting the recovery process; HR n is the heart rate recovery rate after n minutes after the flight; T is the flight duration. Usually n is 5 min. W(t) is the flight duration weighting item. The longer the flight duration is, the smaller the HR n is, which represents the greater the difficulty of heart rate recovery.

[0275] The closer the HR n is to 100%, the closer the heart rate recovery is to the resting state, and the stronger the autonomic nerve regulation ability is; if n = 1 min, HR n > 50%, it is generally considered that the recovery is good; if n = 5 min, HR n > 80%, it is generally considered that the recovery is good.

[0276] ②Calculate the RR recovery efficiency BR n

[0277] The RR recovery efficiency RR n reflects the speed of the pilot's respiratory rate falling from the peak to the resting level after flight.

[0278] During the flight task, the pilot needs to continuously process complex information, leading to sympathetic nerve excitement; at the same time, if there is slight hypoxia in the cockpit, it will trigger respiratory center adjustment, and the combined action of sympathetic nerve excitement and respiratory center adjustment will make the respiratory rate increase from the resting state; after the flight ends, the pilot leaves the stress environment, and the nervous system switches from sympathetic nerve dominance to parasympathetic nerve dominance, and the excitability of the respiratory center decreases; at the same time, the cognitive load and muscle tension decrease, and the body's metabolic rate quickly falls, reducing the demand for ventilation.

[0279] The respiratory rate recovery efficiency evaluates the speed and degree of the respiratory system, autonomic nerve, metabolic perception system, etc. from the stress state to the resting level. Its recovery efficiency directly reflects the heart-lung function reserve, metabolic clearance capacity and overall physiological adaptation state.

[0280] The respiratory recovery rate, i.e. the percentage of the absolute amount of recovery at a certain recovery time point to the total amount of recovery, eliminates the influence of individual resting / peak respiratory frequency differences and is more suitable for evaluating recovery efficiency. RR n The calculation is as follows:

[0281]

[0282] RR rest The average respiratory frequency of the pilot in the state of no flight stress and complete body relaxation is the baseline value within 20 minutes; RR t0 The instantaneous respiratory frequency after the flight ends, reflecting the peak residual level of flight stress; RR tn The respiratory frequency n minutes after the flight ends, reflecting the recovery process; RR n The respiratory frequency recovery efficiency n minutes after exercise. Usually n is 5 minutes.

[0283] RR n The closer to 100%, the closer the respiratory frequency recovery to the resting state, and the stronger the body regulation ability.

[0284] ③Based on the heart rate recovery efficiency HR n and the respiratory frequency recovery efficiency BR n , the cardiovascular system recovery degree CR t is calculated by weighting.

[0285] The evaluation of the cardiovascular system recovery degree is calculated by weighting and integrating the recovery rates of the above indexes. Among them, HR directly reflects the cardiovascular system and has the highest sensitivity, with a weight of 70%; RR indirectly reflects the cardiovascular system, with a weight of 30%; CR t The calculation is as follows:

[0286] CR t = 0.7×HR n + 0.3×RR n Formula (32)

[0287] For the weights of HR n and RR n , they can be changed according to specific needs in specific applications.

[0288] CR t ≥ 80%, indicating that the cardiovascular system recovers well and the fatigue after exercise is relieved quickly;

[0289] 60%≤ CR t < 80%, the recovery is moderate, and the rest time needs to be appropriately extended;

[0290] CR t<60%, recovery slowly, which may indicate that the exercise intensity is too high or the cardiovascular regulation ability is weak. The calculation formula is as follows:

[0291]

[0292] For CR t Threshold 80%, 60%, in specific applications, can be changed according to specific needs.

[0293] (5) Calculate muscle state recovery degree

[0294] Based on the average rectified muscle electrical value AEMG and the average rectified muscle electrical reference value AEMG rest , calculate the average rectified muscle electrical recovery efficiency AEMG n ;

[0295] Based on the average power frequency MPF and the average power frequency reference value MPF rest , calculate the average power frequency recovery efficiency MPF n ;

[0296] Based on AEMG n and MPF n , the muscle state recovery degree is calculated.

[0297] Muscle state recovery degree refers to the degree of recovery of the physiological fatigue state accumulated during flight to the normal physiological state after the pilot completes the flight task. It is a core indicator for evaluating the physiological function repair effect of pilots after flight and judging whether they have the ability to perform flight tasks again, and is directly related to flight safety. Insufficient recovery will lead to inattention, decreased reaction speed, and increased risk of operation failure.

[0298] Muscle state recovery degree, average rectified muscle electrical value AEMG reflects the activation ability of muscle state, and average power frequency MPF reflects the metabolism and fatigue repair ability of muscle. The judgment of muscle state recovery is essentially through AEMG activation ability and MPF fatigue repair recovery rate to quantify the degree of regression of post-flight indicators to baseline. By quantifying the ratio of actual recovery value to theoretical maximum recoverable value after flight, the recovery process is judged.

[0299] ① Calculate AEMG recovery efficiency AEMG n

[0300] AEMG recovery efficiency AEMG n , reflects the speed of AEMG recovery to resting level after flight.

[0301] Average rectified electromyography value AEMG, refers to the average value of the electromyography signal rectified and filtered within a certain time, which is positively correlated with the degree of muscle activation. The tighter the muscle is, the greater the contraction strength is, and the higher the AEMG is. The more relaxed the muscle is, the more sufficient the fatigue relief is, and the lower the AEMG is.

[0302] During flight, the core muscle group of the pilot is in a static working mode, although it does not need to contract greatly, but it needs to maintain tension continuously. This mode will cause the local blood flow of the muscle to slow down, and metabolic waste such as lactic acid and hydrogen ions cannot be removed in time, and after accumulation, they stimulate nerve endings and cause muscle soreness. The motor unit is continuously activated, and the transmission efficiency of the neuromuscular junction decreases, and higher nerve impulses are needed to maintain the original tension, and it gradually increases with the increase of flight time. The heavier the fatigue is, the higher the AEMG is. After the flight ends, the pilot gets rid of the fixed sitting posture, the muscle tension is released, and the body starts the fatigue repair mechanism.

[0303] AEMG is a core index for quantifying muscle activity intensity and fatigue degree, and its recovery efficiency can accurately evaluate the speed and degree of the fatigue muscle returning from a tense state to a relaxed state after flight.

[0304]

[0305] AEMG rest is the average AEMG baseline value of the pilot in the completely relaxed state, which is the baseline value within 20 minutes; AEMG t0 is the instantaneous AEMG measured value after the flight ends; AEMG tn is the AEMG measured value after n minutes of the flight ends, reflecting the recovery process; AEMG n is the AEMG recovery efficiency after n minutes of exercise.

[0306] AEMG n The closer to 100%, the closer the AEMG recovery is to the resting state.

[0307] ②Calculate the MPF recovery efficiency MPF n

[0308] MPF recovery efficiency MPF n reflects the speed of the pilot's MPF recovery to the resting level after flight.

[0309] During flight, the core muscle group of the pilot needs to maintain tension continuously, which causes energy consumption and metabolic waste accumulation, and changes in neuromuscular control, resulting in a decrease in MPF. After the flight ends, the pilot gets rid of the fixed sitting posture, the muscle tension is released, and the body starts the fatigue repair mechanism, which promotes the gradual recovery of MPF.

[0310] MPF, as a core muscle electrical indicator reflecting muscle fatigue degree, its recovery efficiency can quantify the speed and quality of muscle returning to normal functional state from fatigue state after flight, and is a key physiological indicator for evaluating muscle fatigue elimination effect of pilots and ensuring the stability of subsequent flight operation. n The calculation is as follows:

[0311]

[0312] MPF rest is the average MPF baseline value of the pilot in the completely relaxed state, which is the baseline data within 20 minutes; MPF t0 is the instantaneous MPF measured value after the flight; MPF tn is the MPF measured value n minutes after the flight, reflecting the recovery process; MPF n is the MPF recovery efficiency n minutes after the exercise.

[0313] MPF n The closer to 100%, the closer the MPF recovery to the resting state.

[0314] ③Based on AEMG n and MPF n , the muscle state recovery degree is calculated.

[0315] The evaluation of muscle state recovery degree is calculated by weighting and integrating the recovery rates of the above indicators. The calculation is as follows:

[0316] FR t = 0.5 x AEMG n + 0.5 x MPF n Formula (36)

[0317] For the weights of AEMG n and MPF n , they can be changed according to specific needs in specific applications.

[0318] FR t ≥ 85%, indicating complete recovery and normal execution of the next flight task;

[0319] 50% ≤ FR t < 85%, indicating partial recovery, and the rest time needs to be extended, and whether to perform the task is decided after evaluation;

[0320] FR t < 50%, indicating insufficient recovery, and the flight task needs to be suspended and further rest. The calculation is as follows:

[0321]

[0322] For FR t Threshold values 85%, 50%, in specific applications, can be changed according to specific needs.

[0323] The role of step S3 is to quantitatively evaluate the recovery ability of each pilot after flight in multiple dimensions such as brain nerve, autonomic nerve, psychological stress and stress, cardiovascular system and muscle state based on the physiological indicators and individual resting baseline values after each pilot flight.

[0324] Step S4, in particular.

[0325] The rating threshold is set for the five dimensions of brain nerve state recovery degree, autonomic nerve state recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree respectively;

[0326] Based on the rating threshold, each recovery degree is divided into multiple recovery levels;

[0327] Based on the calculated value of each dimension, the recovery level and the corresponding evaluation conclusion of each dimension are obtained;

[0328] Following the principle of the wooden barrel, the evaluation conclusion of the dimension with the lowest recovery level is taken as the final pilot physical and mental state evaluation result.

[0329] Based on the electrocardiogram, respiratory wave, electromyogram and electroencephalogram signals, a multi-dimensional evaluation system of the physical and mental state of the pilot after flight is constructed, including brain state recovery degree, autonomic nervous system recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree. The five dimensions are interrelated and each has its own emphasis, forming a complete evaluation framework. As shown in the radar chart, Figure 2 Through systematic evaluation of the five dimensions, the physical and mental state of the pilot after flight can be comprehensively reflected, providing a scientific basis for the development of individualized training plan and the optimization of recovery strategy.

[0330] The above evaluation method can comprehensively evaluate the recovery state of the pilot after each flight from the physical and mental state. The brain state recovery degree, autonomic nerve recovery degree and psychological stress and stress recovery degree reflect the recovery degree of brain state; the cardiovascular recovery degree and muscle state recovery degree reflect the recovery degree of physical state.

[0331] When the brain state of the pilot recovers well and the physical state recovers poorly, it means that the physiological fatigue needs to be relaxed by physical mechanism such as massage during the task gap.

[0332] When the brain state of the pilot recovers poorly and the physical state recovers well, it means that the psychological fatigue needs to be adjusted, such as mindfulness breathing and cognitive relaxation technique, during the task gap.

[0333] When the pilot's mental state recovery is poor and the physical state recovery is poor, it indicates that psychological fatigue occurs at this time, and the task needs to be suspended and deep rest such as sleep and meditation needs to be performed.

[0334] When the pilot's mental state recovery is good and the physical state recovery is good, it indicates that the physical and mental recovery is good at this time, the recovery efficiency is high, and the task can be continued.

[0335] When the ratings of the five dimensions are inconsistent, the average value cannot be simply taken, the "bucket principle" (the overall performance of the system depends on its weakest link) is followed, and root cause analysis is performed, so as to formulate individualized intervention strategies.

[0336] (1) All five dimensions are excellent, completely released, and the state is excellent, and any task can be performed;

[0337] (2) Any dimension appears to be general, and the specific weak link is judged:

[0338] If the psychological stress and stress recovery rating is general, the release is suspended, the risk is too high, and forced rest or medical intervention is required;

[0339] If the cardiovascular system recovery or autonomic nervous system recovery rating is general, the release or task exemption is limited, the high-intensity task is exempted, and the health management is strengthened;

[0340] (3) None of the five dimensions is general, but there is good, planned release, the state is good, and it is suggested to strengthen the recovery measures.

[0341] Step S4 is to generate a comprehensive evaluation conclusion according to the five-dimensional recovery of the pilot, so as to guide the subsequent flight task arrangement and recovery strategy.

[0342] Embodiment two:

[0343] One specific embodiment of the present application discloses a multi-modal pilot physical and mental state evaluation system based on flight load, thereby realizing the multi-modal pilot physical and mental state evaluation method based on flight load in embodiment one. The specific implementation mode of each module is referred to the corresponding description in embodiment one.

[0344] As shown in Figure 3 A multi-modal pilot physical and mental state evaluation system based on flight load includes an individual resting baseline construction module M1, a post-flight physiological index extraction module M2, and a multi-dimensional recovery evaluation and result generation module M3.

[0345] The individual resting baseline modeling module M1 is configured to collect and pre-process multi-modal physiological signals of the pilots in a resting state, extract resting physical and mental state physiological indicators, and calculate individual resting baseline values of each pilot based on the resting physical and mental state physiological indicators; wherein the multi-modal physiological signals include electrocardiogram, respiratory wave, electromyogram and electroencephalogram signals;

[0346] The post-flight physiological indicator extraction module M2 is configured to collect and pre-process multi-modal physiological signals of the pilots after flight, and extract post-flight physical and mental state physiological indicators.

[0347] The multi-dimensional recovery degree evaluation and result generation module M3 is configured to calculate multi-dimensional recovery degrees of the pilots after flight based on the post-flight physical and mental state physiological indicators and the individual resting baseline values, and generate physical and mental state evaluation results of the pilots based on the multi-dimensional recovery degrees; wherein the multi-dimensional recovery degrees include at least one of brain nerve state recovery degree, autonomic nerve state recovery degree, psychological stress and stress recovery degree, cardiovascular system recovery degree and muscle state recovery degree.

[0348] Since the system in this embodiment is related to the method in Embodiment 1, and the two can be used as reference to each other, this part is repeated and will not be described here. Since the system embodiment and the above-mentioned method embodiment have the same principle, the system embodiment also has the corresponding technical effects of the above-mentioned method embodiment.

[0349] In summary, the multi-modal pilot physical and mental state evaluation method and system based on flight load has the following beneficial effects:

[0350] 1. The present application innovatively integrates four types of heterogeneous physiological signals, namely electrocardiogram, respiratory wave, electromyogram and electroencephalogram, to comprehensively evaluate the physical and mental state of the pilots from multiple dimensions such as cardiovascular system, autonomic nervous system, muscle system and central nervous system, overcoming the defects of the existing technology that relies on a single indicator, resulting in one-sided evaluation results and high risk of misjudgment, and being able to fully and accurately reflect the true fatigue and recovery level of the pilots. The fusion evaluation of multi-modal physiological signals is realized, and the comprehensiveness and accuracy of the evaluation are improved.

[0351] 2. The present application establishes an individual resting baseline value for each pilot, and calculates the recovery efficiency of each physiological indicator based on the individual resting baseline value, completely changing the extensive mode of using group reference values or fixed thresholds in the prior art. This design fully considers the basic physiological differences between individual pilots, making the evaluation results more personalized, scientific and reliable, and effectively solving the problem of poor adaptability of the existing method. By introducing the individual resting baseline, the individual adaptability and accuracy of the evaluation are significantly enhanced.

[0352] 3、The application solves the problem of simple stacking of physiological indexes in the prior art by constructing a recovery degree model of five dimensions of brain nerve state, autonomic nerve state, psychological stress and stress, cardiovascular system and muscle state, and finally generating a unified and hierarchical evaluation conclusion based on the "bucket principle", which provides clear and intuitive task release decision basis for aviation doctors, solves the pain points of lack of system integration and difficulty in direct use for flight decision in the prior art, and improves the decision efficiency of aviation safety management;

[0353] 4、The application first introduces the flight duration of the pilot as a weighted factor into the calculation of heart rate and heart rate variability recovery degree, fills the blank of ignoring the cumulative effect of stress residue in the traditional evaluation, and provides quantitative support for flight safety and health management.

[0354] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing relevant hardware, and the program can be stored in a computer readable storage medium, wherein the computer readable storage medium is a disk, an optical disk, a read-only memory or a random access memory, etc.

[0355] The above is only a preferred specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application.

Claims

1. A multimodal pilot physical and mental state assessment method based on flight load, characterized in that, include: Multimodal physiological signals of pilots in a resting state are collected and preprocessed to calculate resting physical and mental state physiological indicators. Based on these indicators, an individual resting baseline value for each pilot is calculated. The multimodal physiological signals include electrocardiogram (ECG), respiratory wave (RW), electromyography (EMG), and electroencephalography (EEG). The individual resting baseline value includes: Wave baseline value , Wave baseline value , Wave baseline value Heart rate baseline value High-frequency baseline value Low-frequency to high-frequency ratio baseline value Baseline standard deviation of RR interval Root mean square baseline value of the difference between adjacent periods Low-frequency baseline value Respiratory rate baseline Average rectified electromyography reference value and average power frequency reference value ; Collect and preprocess multimodal physiological signals from pilots after flight, and calculate physiological indicators of their physical and mental state after flight. Based on the physiological indicators of the pilot's physical and mental state after flight and the individual's resting baseline value, the pilot's multi-dimensional recovery degree after flight is calculated respectively; the pilot's physical and mental state assessment results are generated based on the multi-dimensional recovery degree; wherein, the multi-dimensional recovery degree includes the recovery degree of brain nerve state, the recovery degree of autonomic nerve state, the recovery degree of psychological stress and stress, the recovery degree of cardiovascular system and muscle state; Rating thresholds were set for the five dimensions: brain nerve state recovery, autonomic nerve state recovery, psychological stress and pressure recovery, cardiovascular system recovery, and muscle state recovery. Based on the rating threshold, each degree of recovery is divided into multiple recovery levels; Based on the calculated value of each dimension, the recovery level and corresponding assessment conclusion for each dimension are obtained; Following the "barrel principle," the assessment conclusion of the dimension with the lowest recovery level will be used as the final assessment result of the pilot's physical and mental condition. Among them, the autonomic nervous system recovery rate is a core physiological indicator used to assess the pilot's physiological function recovery ability and adaptability to subsequent flight missions; the muscle state recovery rate is a core indicator used to assess the pilot's post-flight physiological function repair effect and to determine whether the pilot has the ability to perform flight missions again.

2. The method according to claim 1, characterized in that, The post-flight physical and mental health indicators include heart rate (HR), standard deviation of RR interval (SDNN), root mean square of the difference between adjacent intervals (RMSSD), low-frequency (LF), high-frequency (HF), low-frequency to high-frequency ratio (LF / HF), and respiratory rate. Average rectified electromyography (AEMG), average power frequency (MPF), Wave value, Wave value and Wave value; The calculation of post-flight physical and mental state physiological indicators includes: Based on the electrocardiogram signal, heart rate (HR), heart rate variability time-domain index, and heart rate variability frequency-domain index are calculated; wherein, the time-domain index includes the standard deviation of RR interval (SDNN) and the root mean square of the difference between adjacent intervals (RMSSD), and the frequency-domain index includes low-frequency (LF), high-frequency (HF), and low-frequency to high-frequency ratio (LF / HF); Calculate respiratory rate based on the respiratory wave signal ; The average rectified electromyography (AEMG) value and average power frequency (MPF) are calculated based on the electromyography signals. Calculation based on the EEG signals Wave value, Wave value and Wave value.

3. The method according to claim 2, characterized in that, based on Wave value and Wave baseline value ,calculate Wave recovery efficiency ; based on Wave value and Wave baseline value ,calculate Wave recovery efficiency ; based on Wave value and Wave baseline value ,calculate Wave recovery efficiency ; based on , and The weighted calculation yielded the degree of recovery of the pilot's brain neural state after flight.

4. The method according to claim 2, characterized in that, Based on heart rate (HR) and baseline heart rate Calculate heart rate recovery efficiency ; Based on high frequency (HF) and high frequency baseline values Calculate the high-frequency HF recovery efficiency ; Based on the low-frequency high-frequency ratio (LF / HF) and the low-frequency high-frequency ratio baseline value Calculate the low-frequency to high-frequency ratio recovery efficiency ; based on , and The weighted calculation yielded the pilot's autonomic nervous system recovery rate after flight.

5. The method according to claim 2, characterized in that, Based on the standard deviation of RR interval SDNN and the baseline value of the standard deviation of RR interval ,calculate Recovery efficiency ; Based on the root mean square SD of the difference between adjacent periods and the root mean square baseline value of the difference between adjacent periods Calculate RMSSD recovery efficiency ; Based on low-frequency LF and low-frequency baseline values Calculate low-frequency recovery efficiency ; based on , and The weighted calculation yields the psychological stress and stress recovery rate.

6. The method according to claim 2, characterized in that, Based on respiratory rate and respiratory rate baseline Calculate respiratory rate recovery efficiency ; Based on heart rate recovery efficiency and respiratory rate recovery efficiency The cardiovascular system recovery rate was obtained by weighted calculation.

7. The method according to claim 2, characterized in that, Based on the mean rectified electromyography (AEMG) value and the mean rectified electromyography baseline value Calculate the recovery efficiency of average rectified electromyography value. ; Based on average power frequency (MPF) and average power frequency reference value Calculate the average power frequency recovery efficiency ; based on and The degree of muscle recovery was calculated.

8. A multimodal pilot physical and mental state assessment system based on flight load, characterized in that, It includes an individual resting baseline construction module M1, a post-flight physiological index extraction module M2, and a multi-dimensional recovery assessment and result generation module M3; The individual resting baseline construction module M1 is used to collect and preprocess multimodal physiological signals of pilots in a resting state, extract resting physical and mental state physiological indicators, and calculate the individual resting baseline value of each pilot based on the resting physical and mental state physiological indicators; wherein, the multimodal physiological signals include electrocardiogram signals, respiratory wave signals, electromyography signals, and electroencephalogram signals; The individual resting baseline value includes: Wave baseline value , Wave baseline value , Wave baseline value Heart rate baseline value High-frequency baseline value Low-frequency to high-frequency ratio baseline value Baseline standard deviation of RR interval Root mean square baseline value of the difference between adjacent periods Low-frequency baseline value Respiratory rate baseline Average rectified electromyography reference value and average power frequency reference value ; The post-flight physiological index extraction module M2 is used to collect and preprocess the multimodal physiological signals of the pilot after flight, and extract the physiological indicators of the physical and mental state after flight. The multi-dimensional recovery assessment and result generation module M3 is used to calculate the pilot's multi-dimensional recovery after flight based on the physiological indicators of the pilot's physical and mental state after flight and the individual's resting baseline value; and to generate the pilot's physical and mental state assessment result based on the multi-dimensional recovery; wherein, the multi-dimensional recovery includes the recovery of brain nerve state, the recovery of autonomic nerve state, the recovery of psychological stress and stress, the recovery of cardiovascular system and muscle state; Rating thresholds were set for the five dimensions: brain nerve state recovery, autonomic nerve state recovery, psychological stress and pressure recovery, cardiovascular system recovery, and muscle state recovery. Based on the rating threshold, each degree of recovery is divided into multiple recovery levels; Based on the calculated value of each dimension, the recovery level and corresponding assessment conclusion for each dimension are obtained; Following the "barrel principle," the assessment conclusion of the dimension with the lowest recovery level will be used as the final assessment result of the pilot's physical and mental condition. Among them, the autonomic nervous system recovery rate is a core physiological indicator used to assess the pilot's physiological function recovery ability and adaptability to subsequent flight missions; the muscle state recovery rate is a core indicator used to assess the pilot's post-flight physiological function repair effect and to determine whether the pilot has the ability to perform flight missions again.

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