Cyberwalk

CyberWalk – a holistic approach spanning science, technology and applications to enable unconstrained omni-directional walking in virtual worlds.

Introduction

It is active exploration that enables us humans to construct a rich and coherent percept of our environment. By far the most natural way to interact with large-scale environments is via locomotion. The same should also be true for environments created in Virtual Reality (VR). However, today it is still mostly impossible to freely walk through virtual environments (VEs) in order to actively explore them. The primary reason for this is the scientific and technological underdevelopment in this sector. State-of-the-art walking simulators are usually unidirectional, they do not provide a convincing sense of interaction with the simulated environment, the visualization quality is poor and the scientific fundament for understanding the human-machine interaction is mostly missing.

Cyberwalk's Objectives

It is apparent that at the moment the scientific and technological deficit in the area of walking simulation holds back important developments and many promising applications. In the CyberWalk project we focus on breaking the cycle by pushing research in this field ahead, based on the necessary blend of cognitive/behavioural understanding and high-fidelity technological development, to end up with a fully immersive showcase. To get there, CyberWalk will develop an entirely new concept of an omni-directional treadmill, the CyberCarpet. As envisaged at the moment the walking platform of the carpet will contain a dense 2D matrix of small balls, which are bedded to freely rotate in any direction. The plan is to omni-directionally actuate the balls from below while the user walks on top of the balls. One favoured design is to mount a large conveyor belt on a turntable below this walking platform. The desired rotation velocities of the balls can then be transmitted by friction contacts between belt and balls, whereas friction forces between shoes and balls can manipulate the motion of the user (see B.6/WP2 for details). The exact design of the platform, however, can only be determined after an initial validation of the technical parameters and a profound exploration of the psychophysics of such manipulated walking. To provide the user with an integrated fully immersive Virtual World the CyberCarpet will be combined with visual and auditory input, supplied via a Head Mounted Display (HMD).
The related problems can only be approached systematically if a solid scientific foundation can be established for the underlying perceptual principles. The CyberCarpet development will therefore be complemented from the very beginning by perceptual studies. These will not only provide guidelines for the specific design of an omni-directional treadmill, but will also enhance our understanding of locomotion in Virtual Reality in general, which is essential for such a project to succeed. Basic psychophysical research is therefore central to the CyberWalk project. It will also serve as a benchmark for the evaluation of the technical design concept and its comparison with existing approaches. Psychophysical research ensures that the selected solutions are user friendly. Very little is known about the perceptual basis underlying walking in large-scale virtual environments [Slater95]. Therefore, this strand of psychophysics is challenging and ranges from exploring practical issues like how to hide for the user that s/he is walking on a grid of small balls, to basic scientific questions addressing natural human navigation in virtual worlds. For example, the control system for the linear/angular motion of the platform should incorporate within its design-constraints the psychophysical data on maximum velocity and acceleration (applied force) that a walker may experience without noticing the underlying platform motion, and use then proper smoothing of commands to provide the most natural feeling of free walk. Thus, the psychophysical research conducted within CyberWalk will start from the onset of the project, initially using a simpler setup (uni-directional and circular treadmills, see the work plan for details) before switching to the CyberCarpet design to best cover psycho-perceptual issues related to walking, concerns about the psychophysiology of action, and questions related to multimodal integration.

Reference

http://www.cyberwalk-project.org/index.php?action=showsite&id=234