The research done in this study investigates physiological responses to vertical whole-body vibration. The aim is to determine whether or not quantifiable responses can be found when evaluating changes in breathing rate, heart rate and heart rate variability. Such a relationship could potentially be used in vehicle dynamics industries to improve suspension system designs. This would be done by supplementing subjective testing techniques with a more objective physiological response when evaluating ride comfort.
A group of 60 volunteers were subjected to vertical whole-body vibration using a single seat actuator. The physiological parameters mentioned were measured during three different states, and the changes from state 1-2 and state 2-3 were recorded. The three states were each measured at different stages during the test procedure with stage 1 corresponding to the physiological state 1. Stage 1 consisted of baseline measurements, during this stage the test participant was not exposed to any vibrations at all. During stage 2 the participant was exposed to a reference vibration signal which is identical for all participants, and during stage 3 each participant was exposed to one of 4 alternative signals. The 4 alternative signals are all variants of the reference signal with increased amplitudes. The weighted amplitudes of each alternative signal were increased by 6.47%, 9.57%, 14.64%, and 20% respectively.
After evaluating the recorded data, it was found that the physiological change from state 1-2 was statistically significant for heart rate variability indicators. Unfortunately when evaluating the changes from state 2-3, there had been no statistically significant change. This suggests that while there is a clear and measurable physiological response to the initial vertical whole-body vibration, a change in this vibration is not reflected in the participant’s physiological state.
Dissertation (MEng)--University of Pretoria, 2018.