Experimental Research On Effectiveness Of Pre-Warning Countermeasure Of Driving Fatigue Based On Physiological Signals

Traffic accidents have been an urgent problem of the worlds'countries, and driving fatigue is a significant risk factor in transportation. It is useful to avoid traffic accidents and improve road safety if drivers'fatigue state could be monitored efficaciously, contemporarily, warning is given when fatigue occurs and countermeasures are taken to reduce driving fatigue.Based on the research theories of home and abroad, the paper elaborated reasons and processes and systematically discussed influence factors of perception, estimation, action stage of driving fatigue, and on this basis, research method of pre-warning experimental system of driving fatigue countermeasures effectiveness is generalized and developed based on physiological signals.The paper developed and designed pre-warning experimental system of driving fatigue countermeasures effectiveness, under the existing theoretical basis and experimental equipment. The system contained fatigue detection module, countermeasure generation module and experiment design module. Fatigue detection module is used to collect drivers'physiological signals, judge the drivers'fatigue state according to the variation law of physiological signals with driving time; Once the fatigue was detected the countermeasure generation module would give all kinds of countermeasures, countained sound countermeasure, light countermeasure and viberation countermeasue; Experiment design module was used to design experiment according to scientific method ,and validate the effectiveness of each countermeasure based on statistical analysis of fatigue evaluation indicator.Acording to the applying of pre-warning experimental system of driving fatigue countermeasures effectiveness, the variation of ECG signal and EEG signals before and after an indoor simulated driving task was discussed in the paper. The ECG and EEG indicators, which can characterize the degree and the process of driving fatigue, were identified preliminarily by analyzing the difference of each indicator between before and after driving task. Principal component analysis was used to establish the relationship between ECG and EEG signals and defined the overall index to reduce the volatility of the data and improve the accuracy of fatigue evaluation and by excluding the disturbance of some unnecessary factors. By the reliability verification of the overall index, the result shows that the overall index can not only characterize the drivers'fatigue effectively, but also increase smoothly with driving time during the process of dynamic experiment, which will lay the theoretical principle for the effectiveness of driving fatigue countermeasure.The result of effectiveness validation shows that, the different types of sound, light and vibration have different effects on reducing driving fatigue. Stimulating interval affects driving fatigue mostly, following with sound intensity, frequency and stimulating time of sound stimulus; Stimulating time affects driving fatigue mostly, following with color, luminous intensity and stimulating interval of light stimulus; Stimulating interval affects driving fatigue mostly, following with stimulating time and vibration intensity. Simultaneously, light stimulus is the best of three countermeasures by comprehensive analysis.Scientific methodology of validating the effectiveness of countermeasures against driving fatigue has been formed during the study, which will provide new Ideas and methods for objectively studying on and reducing driving fatigue, provide the experimental platform for validating the effectiveness and safety of all kinds of warning signals.