TRACE: Tactor reach access and constraint environment

Aaron Samuel Bloomfield, University of Pennsylvania


A virtual environment experience of a confined space is usually visually and not physically satisfying. Movement provides excellent visual impressions of the virtual space's shape. But for more precise understanding of the limitations of the virtual world, then visual feedback through the moving eye and disembodied hand are no longer sufficiently adequate paradigms for virtual equivalents of physical presence. What is missing is a more physical sense of the confinement and constraint of the virtual environment. This work addresses these two crucial missing dimensions in interactive immersive environments: confinement and constraint. To address confinement, a partial body suit of tactors provides localized cutaneous vibratory feedback to the user's right arm on areas of collision with the virtual environment. To address constraint, the tactor's haptic feedback is linked to a real-time human figure model. A tactor activates when the corresponding body area collides with the constraint. During movement, the users endeavor to minimize or eliminate tactor sensation. The system includes the tactor hardware and controller, a tactor-based partial body suit, and a computer application interface for tactile feedback during virtual confined space accessibility simulations. The system detects body-to-environment collisions, activates the affected tactors, and drives a real-time display including the scene, the user's avatar, and visual collision feedback. Collision depth is mapped to two discrete tactor frequencies to give the user a better sense of collision severity. The hypothesis is that tactile feedback to body areas provides sufficient guidance to the wearer that the existence and physical realism of access paths and body configurations may be ascertained. The evaluation methodology includes performance measures such as time to complete tasks and number of collisions with the virtual scene. In this dissertation, we present the design and implementation of this system, as well as a series of human subject experiments that validate its empirical performance. The experiments include confined space accessibility studies and skill acquisition exercises. The results clearly show that the use of full arm tactile feedback increases performance in navigating the virtual environment.

Subject Area

Computer science

Recommended Citation

Bloomfield, Aaron Samuel, "TRACE: Tactor reach access and constraint environment" (2003). Dissertations available from ProQuest. AAI3109153.