Virtual Active Touch II: Vibrotactile representation of friction and a new approach to surface shape display

The tactile display for handheld devices requires compact hardware and useful applications. To satisfy these points, we have proposed the concept of `virtual active touch´ that implements virtual exploration with a cursor on a screen through a pointing-stick-type tactile interface. The objective of this study is to present three-dimensional shapes on a two-dimensional screen without force feedback devices. It is possible to present three-dimensional shapes such as a bump using a lateral force. In order to represent human perception of geometric surface shape, instead of the lateral force, we use the cutaneous sensation of friction that occurs when a human finger strokes object surfaces. First, we confirmed that the virtual active touch interface could present cutaneous sense of friction. Second, we evaluated the perception of surface height in the context of bumped shape induced by the friction display. The experimental results agreed with our expectation that faster and longer increases in friction sensation were perceived as higher bumped shapes.