1993 Volume 113 Issue 7 Pages 527-534
To control arousal level using a physiological index has been attempted for some time. However, none of the attempts have enough effects. Because they have two problems. One is a problem in measurement: measuring a physiological index in itself is complicated and creates mental blow to subjects. The other is a problem in contol method: though a relationship between physiological index and arousal level can be detected qualitatively, the detected relationship can not apply to a control. This paper describes a control system for drowsiness which has been developed in order to overcome the problems. Electrodermal activities, which has the superior characteristics of detecting low-arousal-level sensitively, non-restriction and easy operation, was selected out of many physiological indices to overcome the problem in measurment. For the problem in control method, fuzzy inference was introduced in order to apply characteristics, that had been detected qualitatively, of the electrodermal activities in the low-arousal-level to this system. A strict mathemetical model is thereby needless and a manipulated variable can be decided easily with 9 fuzzy rules. It was then confirmed that this system could control drowsiness reasonably from the results of the experiment.