PreloadStep is a novel platform that creates the illusion of walking on different types of terrain in Virtual Reality without requiring users to wear any special instrumentation. PreloadStep works by compressing a set of springs between two plates, with the amount of compression determining the perceived stiffness of the virtual terrain. The platform can render perception of stiffness by applying preload forces up to 824 N in different portions of the terrain, capable of changing stiffness illusion even while a user is standing on it. The effectiveness of PreloadStep was tested in two perception studies (perception thresholds and haptic-visual congruence studies) and an example application, with the results indicating that it is a promising method for creating engaging virtual terrain experiences.
Wooje Chang, Seungwoo Je, Michel Pahud, Mike Sinclair, and Andrea Bianchi, Rendering Perceived Terrain Stiffness in VR Via Preload Variation Against Body-Weight. In IEEE Transactions on Haptics. doi: 10.1109/TOH.2023.3275136.