Haptic effects modulate kinetics of gait but not experience of realism in a virtual reality walking simulator

2008 Virtual Rehabilitation (2008), pp. 36-40, doi: 10.1109/ICVR.2008.4625118
Experiments
Tasks
Findings

Do haptic effects and visual effects affect realism and gait in a virtual reality walking simulator?

Variables

    Haptic Fidelity
  • haptics (on/off) - haptic feedback for ice/mud conditions or none
Independent Variables
System Info

Displays
Input Hardware
Software
None

Biodex unweighting frame

Participant Info

Participants weighed no more than 150 lbs and were no taller than 5'7" (in order to stay within the limits of the walking system) and had no musculoskeletal problems.

Total # Age Range Gender Balance
11 20 - 50

Users crossed a virtual street on a crosswalk, shown on a large screen in front of the user for the visual condition. The street was either in a standard state, an icy state, or a muddy state.

Interaction and Environment

Interface

Users walked naturally across the road by moving their legs in the RMA robot apparati. If the road was in the standard state, the screen was either on or off. If the road was icy or muddy, there was a haptics-only condition, a visual-only condition, and a condition with both. 22 trials were run for each user, with the first two and last two trials the same for each user, crossing the street in its standard state (no ice/mud) with and without visuals (one with and one without each for first/last sets).

The environment was in the form of a street with a crosswalk with other non-interactive objects such as lightpoles and cars shown around the crossing.

Dimensionality Scale Density Visual Realism
2.5D Small High Medium
Metrics

  • presence - visual analogue scale
  • accuracy - velocity and forces of the walking motion.
  1. There was a significant interaction between haptics (on/off) and visual cues (on/off) on presence for a travel - search task.

    Visual cues for the ice and mud conditions resulted in higher realism ratings than the haptics condition. The combination of visual cues and haptic feedback did not increase these ratings.

    Specificity: Somewhat specific

  2. There was a significant direct effect of haptics (on/off) on accuracy for a travel - search task.

    Forces exerted by the user increased in the haptic condition in order to overcome the ice and mud road conditions.

    Specificity: Somewhat specific
    Subject reported that walking with the harness was unnatural and that the shortened step length required by the system interfered with normal walking.