Take a stroll through virtual reality on the CyberWalk omni-directional treadmill
By Darren Quick
November 4, 2009
Jogging on the spot has gone high tech thanks to an omni-directional treadmill that allows you to walk in any direction while staying centered on the treadmill. When coupled with virtual reality (VR) technology it offers the potential for truly natural walking and immersion in virtual environments.
Researchers have been working on various ways to allow a person to physically walk through a virtual environment while remaining in one spot. We’ve seen Powered Shoes that work like reverse roller skates, the VirtuSphere, which is like an oversized hamster ball sitting atop a base of rollers, and the Stringwalker, which supports a person using eight strings actuated by motor-pulley mechanisms mounted on a turntable. The CyberWalk approach is different again in that it is made up of a series of belt treadmills mounted on a conveyor belt of sorts.
The CyberWalk platform basically consists of several belts that provide movement along the X-axis. These belts are in turn mounted on an endless torus that rotates to provide movement along the Y-axis. Think of it like a conveyor belt of conveyor belts. As the two motions can be controlled independently, any resulting motion can be generated to re-center a person on the platform.
The current version of the platform has an active walking area of 4m x 4m, which is roughly the minimum size needed to allow for stable walking without additional support according to its creators. To make the platform any smaller would mean the system would have to react quicker to the movements of the user, which would result in substantially higher forces acting on the user, making them more unstable. While making the system smaller isn’t viable, the modularity of the system means it would be very simple to enlarge – in fact, the bigger the better.
A 3D model of ancient Pompeii was created as a virtual environment to test the CyberWalk system. It allows a user wearing a commercial head mounted display (HMD) to walk around the reconstructed city in any direction and enjoy the sights hours before the eruption of Vesuvius. The HMD has markers on it to provide fast and accurate visual feedback to the wearer, while cameras are used to track the position and posture of the user to help control the velocity of the treadmill and interactions with the virtual environment.
Interestingly the CyberWalk platform wasn’t the initial vision the project team had for an omni-directional treadmill. The original plan involved a ball bearing platform called a CyberCarpet that sees a dense 2D matrix of small balls that are bedded to freely rotate in any direction acting as the surface of the platform. A fully functioning prototype measuring around 80 cm in diameter was built, which can be seen in the video below, but the team realized that this design was too difficult to scale up to a size that would be required for natural human locomotion.
While entertainment is the use for the technology that first springs to mind with fully immersive virtual reality games sure to appeal to gamers, the potential applications are immense. Architects could experience and explore a building before it is constructed. Emergency services personnel could be trained how to deal with all manner of situations. Or it could help people with medical rehabilitation after a stroke, those with Parkinson’s disease, or those who need help overcoming phobias.
The CyberWalk project was an EU funded research project which finished last year. The omni-directional treadmill is now in a research lab at the Max Planck Institute for Biological Cybernetics in Tuebingen, Germany, where it is used to study human perception and action. Since all the partners involved in the development of the treadmill were research partners there are currently no plans to commercialize it. However Dr. Marc O. Ernst at the Institute says if there was a company interested in doing so, they would certainly help. It seems a shame not to see this technology put to wider use, so we'll keep our finger's crossed it attracts some interest from someone willing and able to develop the treadmill further.
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