A Computational Model of Motion Sickness Considering Visual and Vestibular Information

Abstract

Interest for motion sickness is increasing with increasing opportunities to view digital devices in transportation systems, including automated vehicles. Hence, technology for predicting and estimating motion sickness is essential. As one such technology, computational models for estimating motion sickness from head movements have been proposed and are used for motion sickness evaluation. However, a model capable of handling the effects of visual input and the visual-vestibular interaction for motions with six-degrees-of-freedom has yet to be developed. In this study, therefore, a computational model of motion sickness with visual-vestibular inputs is proposed by extending a model of the subjective vertical conflict theory of motion sickness for a vestibular input only. The proposed model inputs are the acceleration and angular velocity of the head and the visual perception of the angular velocity. A simulation conducted by inputting 1 h of sinusoidal oscillations demonstrated that the results are consistent with those of similar experiments conducted with human participants. In addition, the results of a simulation experiment conducted by changing the visual input demonstrated that motion sickness increases significantly when a conflict occurs between the visual and vestibular signals, which imitates the reading of a book in a moving car. Furthermore, we developed a method to calculate the predicted MSI using experimental data measured by IMU and camera image by approximating the visual perception of the angular velocity through an optical flow analysis. The results of inputting camera images and inertial measurement unit signals obtained by sine-wave-like pitching motion into the proposed model demonstrate that the proposed method, can describe the difference in motion sickness by the changes in the visual environment.