Motion Sickness During Low Frequency Lateral and Roll Motions in Isolation and in Combination: Effect of Visual Conditions with/without VR HMD Device

Abstract

Motion sickness has been a common issue that impacts the comfort of passengers in road transport due to exposure to low frequencies of horizontal and rotational motions. Previous work found that exposure to lateral and roll motions in isolation and in combination can cause motion sickness in road transport; however, the role of visual scene on incidence of sickness during these motions is unclear. The main objective of this thesis was to investigate the effect of visual activity with/without a VR HMD device on incidence and severity of motion sickness induced by three typical road motions, including lateral oscillation, roll oscillation and combined lateral and roll oscillation. The first experiment investigated the effect of an HMD view, a monitor view and no view (blindfold) on motion sickness induced by low-frequency lateral oscillation. Subjects were exposed to sinusoidal low-frequency lateral oscillation at 0.25 Hz with an acceleration magnitude of 0.61 ms−2 r.m.s. (a displacement of ± 248 mm). Motion sickness was greatest with the monitor condition, less with the HMD condition and least with the blindfold condition. In the second and third experiments, the effect of an HMD view and a monitor view on severity of motion sickness was examined during sinusoidal low-frequency roll oscillation at 0.25 Hz with an angle of rotation (±5°) and combined lateral at 0.25 Hz with an acceleration magnitude of 0.61 ms−2 r.m.s. (a displacement of ± 248 mm) and roll oscillation at 0.25 Hz with an angle of rotation (±5°) with no phase difference, respectively. Consistent findings indicated that the HMD view significantly resulted in less sickness compared to the monitor view. The fourth experiment tested the effect of congruent/incongruent visual information and motion with/without the use of a VR HMD device on severity of sickness during exposure to the three motions. There were no significant differences between the three motion directions during exposure to a congruent visual content with motion; however, the combined lateral and roll motion caused greater sickness than either lateral motion or roll motion. The incongruent visual content with motion significantly caused higher sickness than the other visual conditions. The congruent visual content with motion reduced severity of motion sickness induced by all the three motions. The outside view (no VR) resulted in the least sickness relative to all conditions. The findings of experimental work indicate that there is a significant effect of the visual activity on motion sickness induced by either lateral, roll or combined lateral and roll motions. Although the visual contents presented through the VR HMD device found to incidence of sickness, factors including individual differences, content and specifications of a display system might limit its benefits and affect experience of some subjects. The applications of VR could be improved to further reduce motion sickness in road transport.