Comfortable awakening method for sleeping driver during autonomous driving

There is a high possibility that the driver who is relieved from driving will suffer from sleepiness and there is a limit to keeping the driver awake in the system, which may cause a loss in comfort during autonomous driving. In this study, we propose a method for a comfortable awakening by installing a device that can wake up the driver as a safety function in case the driver falls asleep during autonomous driving. We have used existing devices to investigate the stimulation to the driver's five senses through the use of vibration, aroma and facial stimulation and we have evaluated a human machine interface (HMI) device that allows the driver to comfortably wake up from sleep using a driving simulator. The accuracy of driver operation was evaluated as well as physiological indices for heart rate changes before/after awakening and eyelid opening/closing times after waking up. Facial stimulation with air blowing devices (such as air conditioners) was the quickest way for the driver to return from autonomous driving to manual driving. We have shown that existing devices can be used as an HMI for comfortable awakening by applying airflow to the face.