Effects of Head Orientation on Head/Helmet Vibration Response

摘要

Involuntary head/helmet motion due to vibration can compromise the effective use of helmet-mounted cueing systems. Extreme off-axis head/helmet orientations are also expected during tactical maneuvers where aircraft vibration occurs. The effects of head/helmet orientation on head/helmet low frequency vibration response were investigated. Subjects were exposed to an experimental F-15 vibration signal and to sinusoidal frequencies in the range of 3 to 10 Hz. Head and helmet rms accelerations, power spectral densities, and transmissibilities were evaluated. The results showed that head/helmet orientation had minimal effect on the frequency location of the peak responses, which primarily occurred between 4 and 7 Hz for both types of exposures. However, significant increases in the peak helmet pitch responses were observed for head/helmet orientations not aligned with the vertical input axis at the seat. For these off-axis orientations, both exposures showed responses, which tended to be higher at most frequencies below 10 Hz. These head/helmet response characteristics can provide important criteria for developing hardware damping mechanisms and/or software algorithms, which minimize the effects of head/helmet motions on tracking performance and cueing system stability.