Head and helmet biodynamics and tracking performance in vibration environments

Smith, Suzanne D.; Smith, Jeanne A.

Affiliations

¹Human Effectiveness Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH

²General Dynamics AIS at Wright Patterson AFB, OH

Abstract and keywords

Introduction: 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 (CG) on head and helmet biodynamics and tracking performance during exposures to aircraft buffeting and quasi-random vibration.

Methods: 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 CGs were tested. The overall head, helmet, and helmet slippage displacement rotations, and rms tracking error and percent time-on-target were evaluated.

Results: For both exposures, the two off-axis orientations produced 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 CGs during aircraft buffeting, with minimal degradation observed with the quasi-random exposure. Higher head pitch and lower pitch slippage were associated with the CG estimated to produce loading behind the human head CG.

Conclusions: 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 moments-of-inertia of the helmet system may also have a significant influence on both head/helmet biodynamics and tracking performance and should be investigated.

Keywords: head tracking performance; helmet-mounted systems; whole-body vibration

Links

PubMed: 16676649

WoS: 000236712900002

History

Received: 2005-04

Accepted: 2005-12

Cited Works (3)

Year	Entry
1980	Beier G, Schuller E, Schuck M, Ewing CL, Becker ED, Thomas DJ. Center of gravity and moments of inertia of human heads. In: Proceedings of the 1980 International IRCOBI Conference on the Biomechanics of Impact. September 9-11, 1980; Birmingham, England.218-228.
2004	Smith SD. Cockpit seat and pilot helmet vibration during flight operations on aircraft carriers. Aviat Space Environ Med. March 2004;75(3):247-254.
2000	Barazanji KW, Alem N. Effects of Head-Supported Devices on Female Aviators During Simulated Helicopter Rides, I: Biomechanical Response. Fort Detrick, MD: U.S. Army Medical Research and Materiel Command; June 2000. Usaarl Report 2000-16.

Cited By (3)

Year	Entry
2013	Äng BO, Kristoffersson M. Neck muscle activity in fighter pilots wearing night-vision equipment during simulated flight. Aviat Space Environ Med. February 2013;84(2):125-133.
2015	Tung K, Miller M, Colombi J, Uribe D, Smith S. Effect of vibration on eye, head and helmet movements while wearing a helmet-mounted display. J Soc Inf Disp. October 2015;22(10):535-544.
2013	Ciloglu H. Experimental and Numerical Investigation of the Dynamic Seat Comfort in Aircrafts [Master's thesis]. University of Ontario Institute of Technology; 2013.