A Mathematical Model of Motion Sickness in 6DOF Motion and Its Application to Vehicle Passengers

A mathematical model of motion sickness incidence (MSI) is derived by integrating neurophysiological knowledge of the vestibular system to predict the severity of motion sickness of humans. Bos et al. proposed the successful mathematical model of motion sickness based on the neurophysiological mechanism based on the subject vertical conflict (SVC) theory. We expand this model to 6-DOF motion, including head rotation, by introducing the otolith-canal interaction. Then the model is applied to an analysis of passengers’ comfort. It is known that the driver is less susceptible to motion sickness than are the passengers. In addition, it is known that the driver tilts his/her head toward the curve direction when curve driving, whereas the passengers' head movement is likely to occur in the opposite direction. Thus, the effect of the head tilt strategy on motion sickness was investigated by the proposed mathematical model. The head movements of drivers and passengers were measured in slalom driving. Then, the MSI of the drivers and that of the passengers predicted by the proposed model were compared. The results revealed that the head movement toward the centripetal direction has a significant effect in reducing the MSI in the sense of SVC theory.