Walking is the most natural way for humans to navigate through their environment. Until recently it was almost impossible to physically walk through Virtual Environments in an unconstrained way. In the EU project "CyberWalk" an omnidirectional treadmill was developed, which together with real-time tracking, optimized control and several perceptual tricks enables humans to walk through Virtual Worlds in an natural and unconstrained fashion.
The CyberWalk treadmill is an ideal tool to study the interaction between perception and locomotion. Research topics include, but are not limited to: walking behavior, speed perception during walking, statistics of natural walking behavior, multisensory integration, and human navigation. The user wears a Head Mouted Display /HMD) which shows the Virutal Environment., Both the head and the body of the user are tracked. The head position and orientation are used to update the view of the Virtual Environment in the HMD, so that is corresponds to the way the user moves the head. The body position is used to control the treadmill, keeping the user close to the centre of the treadmill. Changes in treadmill speed and direction are kept below levels that would interfere with normal walking.
Together with CyberWalk partners from the Technical University in Munich, from the University La Sapienza of Rome and from the Swiss Federal Institute of Technology in Zürich, we have developed a revolutionary omnidirectional treadmill. It is the first omnidirectional treadmill in the world that allows for near-natural walking through arbitrarily large virtual environments and that can be used for basic research. The basic mechanism consists of 25 belts (0.5m wide) that are mounted on two big chains. The chains constitute one motion direction (1.4 m/s), while the belts run in the orthogonal direction (1.4 m/s). Together, they can generate motion in any direction. The chains move 7 tons, driven by 4 large 10 kW frequency-coupled engines. The treadmill measures 6.5 x 6.5 x 1.45m (LxWxH), with an active walking surface of 4.0 x 4.0m. Position of the person on the treadmill is measured with a Vicon tracking system and used to adjust the treadmill velocity as a function of walking speed. Together with a head-mounted display or panoramic projection screen (planned), the treadmill system allows users to walk through large virtual environments in a natural way.