Investigating perceived slope gradient in virtual environment with visuo-haptic interaction

Virtual reality games with head-mounted display shows players rough terrain, such as slopes and steps, in the virtual world. The players in the real world, however, have to take walking action on a flat floor. The gap can be considered to reduce the immersion of the players. The objective of this study is to improve the reality of a virtual reality application in which the user walks up a slope. In this paper, we describe the hypotheses about cross-modal interaction between visual and haptic stimuli. We also describes the prototype system that can change the visual angle of the slope in virtual environment and the haptic angle of the slope in real environment. We conducted a demonstrative experiment at a symposium with this prototype. Although we could not obtain enough data to verify the hypotheses, we confirmed some important findings to improve the usability of the prototype system.