Head and Helmet Biodynamics and Tracking Performance in Vibration Environments
Interim rept. Jul 2004-Mar 2005
GENERAL DYNAMICS ADVANCED INFORMATION SYSTEMS DAYTON OH
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There are potential effects of vibration on aircrew performance and safety when using helmet-mounted equipment The objective of this study was to quantify the effects of head orientation and helmet center-of-gravity CC on head and helmet biodynamics and tracking performance during exposures to aircraft buffeting and quasi-random vibration. Three head orientations, including two off-axis or off-boresight configurations Side 40 elevation, 70 azimuth and Up 40 elevation, 0 azimuth, and three helmet CCs were tested. The overall head, helmet, and helmet slippage displacement rotations, and rms tracking error and percent time-on-target were evaluated. For both exposures, the two off-axis orientations produced sign significantly higher head, helmet, and slippage displacements a relationship was observed between the orientation and the rotation that was affected roll, pitch, or yaw. The highest slippage observed was in pitch in the forward For and Up orientations. Significantly higher performance degradation occurred with the Side orientation for two of the three CCs during aircraft buffeting with minimal degradation observed with the quasi-random exposure. Higher head pitch and lower pitch slippage were associated with the CC estimated to produce loading behind the human head CC. The high off-boresight head movements may influence visual performance in operational vibration environments. Helmet instability appeared to be the greatest in pitch, which could have a significant effect on the design size of the exit pupil. The weight distribution or moment-of-inertia of the helmet system may also have a significant influence on both headhelmet biodynamics and tracking performance and should be investigated.
- Stress Physiology
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