자동차 공조 환경이 인체 감성신호에 미치는 영향에 대한 실험적 연구

Abstract

To investigate the comfort and satisfaction in the automobile HVAC environment, the EEG and PPG of subjects in the vehicle were measured and the questionaries were investigated during simulation driving when the cabin and vent exit temperature was set for heating and cooling condition. As a result of questionaries in the heating experiment, the TSV and CSV increased simultaneously as the cabin and vent exit temperature increased at the beginning of the experiment. That means the psychologic stability and satisfaction under the given environment was so good. When the cabin and vent exit temperature changed from 15℃ and 40℃ to 20℃ and 35℃, SDNN and RMSSD was suppressed and LF/HF increased, thus it was clear that the sympathetic nervous system was activated. After cabin and vent the temperature increased more, the subject could not focus on the driving and felt the boredom and drowsiness. The analysis results of the EEG in the heating experiment, the relative β wave, the concentration and the brain wave activity(β/α) at the frontal lobe were maintained until the cabin temperature of 20℃ and vent exit temperature of 35℃. Whereas, the relative θ and α power at the occipital lobe increased when the cabin temperature was 22.5℃ ～ 27.5℃ and the vent exit temperature was 32.5℃ ～ 27.5℃. This indicated the subjects felt boring and sleeping. As the result of the cooling experiment, the subjective questionaries investigation about the thermal comfortability presented that the thermal sensation decreased but the comfortability increased as the cabin temperature increased. In particular, the psychosomatic stability and satisfaction of the subjects were high at the beginning of experiment. As the analysis of PPG in the cooling experiment, the stress index was barely changed except the cabin temperature of 30℃ and the vent exit temperature of 16.5℃. LF/HF increased based on of the cabin temperature of 27.5℃ and the vent exit temperature of 18.5℃, thus the arousal lever was maintained. Previous studies showed SDNN and RMSSD decreased under the unpleasant condition. However, as the results of this study, the SDNN and RMSSD did not decrease significantly because of the influence of the vent exit temperature. As a result of analyzing the EEG in the cooling experiment, the relative β wave, the concentration and the activity of the EEG of left-frontal lobe increased, while the relative θ wave decreased. The relative θ wave decreased at the cabin temperature of 30℃ and the vent exit temperature of 16.5℃. However the relative β wave and the concentration increased continuously. The relative β wave of the right-frontal lobe increased significantly and the concentration decreased when the cabin temperature and the vent exit temperature was 22.5℃. It can be inferred that the body recognized unpleased condition because sensory temperature decreased owing to a low temperature of the vent exit air. In the analysis EEG of occipital lobe in the cooling experiment, the relative α wave showed a little change. The relative α wave of occipital lobe did not largely change except the cabin temperature of 25℃ and vent exit temperature of 20.5℃. To investigate the difference on the bio-sensibility according to temperature in the cooling and heating experiment, the statistical analysis was carried out by using the independent sampling techniques which was known as non-parametric testing method. In the statistical analysing method very result, each results has significant difference because the significance probability of all variables was lower that 0.05 the as significance mean level. The statistical analysis in cooling experiment was also carried out. As a result, all variables has a significant difference in thermal and comfortability questionnaires and the PPG difference. However, in case of the brain wave, the significant difference didn't have the meaning because the significance probability on the brain activity and the concentration of the right-frontal lobe was 0.101 and 0.206, and it of the relative θ wave at the occipital lobe was 0.429.