A Simulator Sickness Literature Review Michael A. Mollenhauer 12/19/2003

Project Background US Army TACOM Funded SBIR (Phase 2) CAVE-Based Driving Simulator with Mini-Motion Base for Off-Road Driving End Goal: Virtual Vehicle Design Platform Understand How Different Configurations Effect Driving Performance and Simulator Adaptation Syndrome

Research Issues Visuals Presentation –HMD vs. CAVE Stereo vs. CAVE Mono Motion Tuning Parameters –Degrees of Freedom –Motion Scaling –Response Frequency Display Configurations –Wide vs. Narrow FOV –Curved vs. Flat Screens

Driving Environment

Literature Review Task 144 Papers Reviewed / 120 Incorporated Search Topics Included Various Aspects Of –Simulator Sickness –Driving Simulation –Motion Cueing –Visual Displays for Simulation –Virtual Environments –Driving Performance –Simulator Validation –Off-Road Driving

Document Outline The Simulator Sickness Issue Theories of Simulator Sickness Important Aspects of Visual System Important Aspects of Vestibular System Simulator Design Factors –Field of View –Display Flicker –Image Resolution –Graphics Update Rate –Display Refresh Rate –Mono, Stereo –HMDs –Motion Cueing –System Calibration –Transport Delay –Environmental Conditions –Simulator Adaptation –Visual Vehicle References –Independent Visual Background

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Interesting New Research University of Washington, HIT Lab Prothero, J., Hoffman, H., Furness, T., Parker, D., and Wells, M. (1995) Began exploration of rest frames and the impact they have on vection and presence Rest Frame Hypothesis

Rest Frames in Spatial Perception Perception of space depends on reference frames from which judgements of position, orientation, and motion are derived Reference frame taken to be stationary is called the selected rest frame and this processing occurs at sub-conscious level Subjective rest frames can be formed incorrectly resulting in illusory perceived self-motion (vection) and illusory self-position and orientation (presence)

Rest Frames in Virtual Environments How is rest frame selected? Major determinant  what is perceived to be “background” Example: Induced motion - illusion of watching another car out the window at a stoplight –Other car moves forward but you feel as though you are moving backwards –Other car has been accepted as background and sensory systems perceive it to be stationary

Relationship to Simulator Sickness Sickness does not occur from conflicting cues but rather from conflicting rest frames deduced from various virtual environment stimuli (Prothero, Draper, Furness, Parker, and Wells, 1999) To avoid sim sickness – do not remove all conflicting motion cues but rather remove discrepancies that indicate conflicting rest frames

Independent Visual Background Hypothesis: Presenting an independent visual cue in background that is consistent with inertial cues may reduce sickness even if not in agreement with foreground cues (Prothero, Draper, Furness, Parker, and Wells, 1997)

Supporting Research Prothero, J., Draper, M., Furness, T., Parker, D. and Wells, M. (1999) –See-through vs. occluded background HMDs –See-through HMD with stable background resulted in lower SSQ and Ataxia measures but did not affect vection ratings –Second experiment added a task that required attention in the content of interest and duplicated results

Additional Research Duh, Parker, and Furness (2001) – frequency of stimuli and IVB brighness –IVB reduced ataxia for low frequency stimuli.05 Hz vs.8 Hz –More effective with brighter IVB Duh, Abi-Rached, Parker, and Furness (2002) – depth in stereo displays –IVB reduced ataxia –No differences reported for varying the depth of IVB presentation

Additional Research (cont’d) Duh, Parker, and Furness (2003) – central vs. peripheral vs. both IVB presentation –Less balance disturbance with IVB in central vision Lin, Abi-Rached, Kim, Parker, and Furness (2002) – tested IVB in driving simulator, grid and natural cloud formations –Natural IVB reduced SSQ scores more than grid on drive sim with complex scene –More clouds, more benefit (could be due to increased luminance caused by clouds)

Questions for General Application Potential for motion induction in complex, realistic virtual environments – does complexity matter? Impact of IVB on subject attention and acceptance? How to apply IVB in virtual environments with motion cueing systems?