Research On Key Techniques Of Mental Fatigue Perception And Feedback Based On Physiological Signals Of Heart And Brain

With the rapid development of economy and society,people’s pursuit of a better life is always accompanied by high-intensity and fast-paced work tasks,and the resulting mental fatigue often leads to physical and mental exhaustion,which may affect work efficiency or cause work errors in minor cases,or lead to mental illness or major safety accidents.Therefore,percepting human mental fatigue for early warning and regulating mental fatigue is of great practical significance to promote people’s health management and avoid accidents.In recent years,devices for sensing mental fatigue have been widely studied by researchers,and detection means based on physiological signals are favored due to their high reliability and accuracy,but most of these devices have not been more popularly used because of their fixed use scenarios,troublesome wearing and short use time.In addition,most of the current market devices use the way of monitoring mental fatigue based on human behavior,which is less reliable and does not have the ability of feedback adjustment of mental fatigue.Based on this background,relying on the Science and Technology Innovation 2030 Major Projects,this paper designs and implements a physiological signal-based mental fatigue perceoting and feedback system,which has the advantages of simple operation,easy portability and diversified use scenarios.The system focuses on four key points: portability,physiological signal acquisition and processing,mental fatigue perception and music feedback regulation,and the main research contents and results are as follows:(1)Implementation and validation of portable physiological signal acquisition and audio playback system.The overall size of the hardware circuit board of the acquisition system is 60mm×30mm×12mm,using dry electrodes to acquire electroencephalogram signals in the prefrontal poles hairless area Fp1,Fpz and Fp2 regions of the human head,using piezoelectric film to acquire ballistocardiogram,and using bluetooth wireless communication to transmit physiological data.The device as a whole is very portable and easy to use.For the characteristics of electroencephalogram and ballistocardiogram signals,such as small amplitude,low spectral range and susceptibility to interference,we analyze the difficulties of acquiring signals and build an acquisition model,and realize the design of hardware acquisition circuit for physiological small signals and digital signal pre-processing algorithm based on wavelet transform and adaptive filtering.In order to make it more intuitive for users to use,a Qt-based upper computer interactive interface is designed,which can display physiological signal data in real time and store them.An audio playback module is designed to receive commands from the host computer and play music.In addition,the physiological signal pre-processing algorithm was functionally verified,and the algorithm achieved the purpose of removing interference such as electrooculography and motion artifacts,and the acquisition system successfully acquired electroencephalogram signal α wave and periodic ballistocardiogram.Finally,the physiological signal acquisition system was partially verified for basic performance such as noise level,common mode rejection ratio and polarization resistance voltage according to the national medical device certification standards,and the verification results were all within the range of the JJG954-2019 Digital EEG Instrument standard,and a portable physiological signal acquisition and music playback device was successfully realized.(2)A simulated experiment of mental fatigue evocation and feedback regulation was constructed,and the physiological signal feature extraction and mental fatigue classification algorithm were implemented.A high fall and high exertion mental fatigue evocation paradigm was designed,and a total of 30 subjects participated in the simulation experiment,divided into control and experimental groups,and the subjects’ mental fatigue status was detected by the Stanford Sleepiness Scale and the portable physiological signal acquisition system.The spectral features of electroencephalogram signal(α + θ)/β,the standard deviation of ballistocardiogram interval SDN N and the spectral features of ballistocardiogram interval LF/HF were extracted from the subjects.The data sets of mental fatigue and wakefulness physiological features were established by the scale results corresponding to the physiological data feature indexes.The results from the simulation experiments showed that the statistical characteristics of the three characteristic indexes in the mental fatigue state were consistent with the existing domestic and international studies,and the effect of music feedback in regulating mental fatigue was obvious.The support vector machine model was used to train and classify the mental fatigue and wakefulness physiological data sets,and the accuracy of both wakefulness and fatigue classification was above 85%.In summary,this paper designed and completed a set of mental fatigue perception and feedback regulation system based on physiological signal.The key parts such as small signal hardware acquisition circuit design,digital signal pre-processing algorithm,feature extraction and classification algorithm are studied and verified in detail.On this basis,simulation experiments on mental fatigue evocation and musical feedback regulation are carried out.The system realize the normalized monitoring and feedback regulation of mental fatigue in people’s daily life.