A comparison of different methods for reducing the unintended positional drift accompanying walking-in-place locomotion

If Walking-in-place (WIP) techniques are to be considered a useful way of facilitating virtual locomotion, it is crucial that the user remains stationary with respect to the physical environment. However, it has recently been documented that WIP locmotion may lead to Unintended Positional Drift (UPD). Users walking in place while wearing a head-mounted display tend to physically drift in the direction which they are headed within the virtual environment. This paper details a within-subjects study evaluating different methods for minimizing UPD. The study included 14 conditions: 13 different types of feedback informing the user that a certain amount of drift had occurred and a control condition devoid of feedback. The feedback differed in terms of sensory modality (auditory, visual or audiovisual), onset mode (gradual or sudden) and presentation mode (either the feedback constituted a warning or a deprivation of the stimuli used to represent the virtual world). Finally, a condition providing passive haptic feedback (a circular carpet) was included. The types of feedback were assessed in terms of how effectively they reduced UPD as well as how helpful and intrusive they were perceived. The results suggest that both passive haptic feedback and feedback types with gradual onset are the most efficient at controlling the user's physical movement. However, the passive haptic feedback was regarded as more helpful and perceived as less disruptive than some of the feedback types with a gradual onset.