[YouTube - Link]
"One of the big problems facing VR is the issue of mobility -- how do you allow users unrestricted movement in virtual reality, while keeping them relatively static in real reality?
Omni-directional treadmills have been tried in the past, and now researchers at the University of Tsukuba in Japan have developed something called CirculaFloor. The system uses four robotic tiles that constantly shift position, ensuring that there's always a tile in the direction you're headed.
Additionally, the entire assembly moves slowly backwards, giving one the impression of movement while they're actually standing relatively still. The tiles also incorporate lifts, for simulating staircases and the like."
- via engadget
From the Upcoming ueue, submitted by Geekazoid.
I've personally test-driven a system that used roller skate like devices strapped to the feet and a stabilization/directional bar. As you walked, the roller skatey things on your feet sensed when your foot was on the ground and motors inside them moved your foot backward a pre determined distance. After only a minute of acclimatisation I was roaming freely in a virtual neighborhood, navigating turns and moving along at a pretty good speed.
My favorite idea so far though has to be the fixed platform whose surface is omnidirectional. Lots of sensors and reaction mechanisms for that design though.
As somebody else said, putting the VR user in a giant hamster ball that rolls in place is almost certainly a better idea.... the only problem being a lack of height differential.