title: Head roll compensation in a visually coupled HMD: considerations for helicopter operations.
abstract: BACKGROUND
  The helmet-mounted display (HMD) research program at the Flight Research Laboratory of the National Research Council of Canada examined the effects of HMD camera platform dynamics on pilot workload. Many currently fielded visually coupled HMD systems do not reproduce head movements in the roll axis which can lead to the presentation of visual information that is not consistent with vestibular and proprioceptive information.
  
  
  OBJECTIVE
  Our hypothesis was that this sensory conflict can induce motion sickness and increase pilot workload.
  
  
  METHODS
  To examine this premise, three pilots flew a series of standardized maneuvers with or without roll compensation in the camera platform of a visually coupled HMD system.
  
  
  RESULTS
  Increases in motion sickness symptoms and pilot workload were noted during complex, high-workload maneuvers when no roll compensation was present in the camera platform. During the most demanding maneuvers, the lack of roll compensation in the camera platform made it difficult for the evaluation pilot to control the helicopter.
  
  
  CONCLUSIONS
  Roll compensation in visually coupled HMD systems reduces pilot workload and' motion sickness during critical flight periods where pilot workload may already be considerable.
authors.affiliation: Flight Research Laboratory, National Research Council of Canada, Ottawa, Ontario. greg.craig@nrc.ca
authors.forename: G L
authors.initials: GL
authors.lastname: Craig
authors.forename: S A
authors.initials: SA
authors.lastname: Jennings
authors.forename: C P
authors.initials: CP
authors.lastname: Swail
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000401:Aircraft; D003623:Dark Adaptation; D004867:Equipment Design; D005139:Eyeglasses; D019416:Head Movements; D006801:Humans; D008297:Male; D008875:Middle Aged; D009041:Motion Sickness; D011187:Posture; D014796:Visual Perception; D016526:Workload