Performance and Usability of Force Feedback and Auditory Substitutions in a Virtual Environment Manipulation Task

Recent technology developments have made possible the creation of several commercial devices and a selected number of development platforms for the inclusion of haptics (the sense of touch) in virtual environments (VE). This thesis sought to investigate and develop a better understanding of whether or not haptics or sound substitutions improved manipulation performance or usability in VE applications. Twenty-four volunteers (12 males and 12 females) participated in a 2 (haptics) x 2 (sound) x 2 (gender) mixed factorial experiment in which they completed a VE manipulation task involving the assembly and disassembly of 5 interconnecting parts. Performance for the manipulation task was measured through completion time and the number of collisions made, as well as subjective measures of usability.

Results indicated that completion times were slower and collision counts were higher for males with the addition of haptics (ptime = 0.03; pcollisions<0.05), while females exhibited a smaller increase in collision counts and no increase in completion time with the addition of haptics. Nonetheless, there were improved usability attributes when haptics were incorporated, more specifically, an increased sense of realism, perceived helpfulness and perceived utility in a design task (p<0.05 for all). Sound was found to be an effective substitute for haptics in most measures taken while the combination of sound and haptics versus either alone, did not demonstrate any signs of improving performance or any usability attributes. It is therefore recommended that sound substitution be used in VE manipulation tasks where the extra haptic information is desired, and minimizing completion time or collisions are the overall goal. Finally, for the utility of the feedback towards a design task, users ranked haptics as being more useful than sound, but ranked the combination of sound and haptics as being the best feedback condition (p<0.05). Further research is required to determine whether this belief is consistent with objective measures.