Influence of steering intention on postural control strategies in older adults during sudden turning on a stand-up type PMV

In recent years, personal mobility vehicles (PMVs) have attracted attention as a new means of transportation for older adults. In general, PMVs have the advantage of being compact and maneuverable, but both the rider and vehicle have a high center of gravity, which may cause the rider to lose their balance. In this study, we investigated the dynamic characteristics of PMV riders during sudden turns and clarified differences in behavior with respect to age, as well as how these differences vary depending on driving conditions, through vehicle experiments. Measurements revealed that the rider's center of gravity (COG) tended to shift toward the inside during turns. Additionally, through the analysis of the time series changes in joint moments, it was observed that younger individuals tend to apply force to upper-body joints such as the shoulders, elbows, and wrists, while older individuals tend to concentrate force on lower-body joints such as the knees and hips to control posture. Furthermore, older riders were found to apply force in advance in a direction opposing motion centered on the hip joint, revealing the characteristics of their posture control strategy.