Virtual active touch: Perceived roughness through a pointing-stick-type tactile interface

For realizing a tactile display for a handheld device, active touch movement should be represented on a small interface. We propose the addition of a tactile feedback mechanism for a pointing-stick-type (PS) input device. In this study, we describe a method for enabling virtual active touch with a cursor on the screen operated by the PS-type tactile interface without actual touch movement. First, to validate our concept, we compared tactile detection capabilities of roughness information represented by the PS-type tactile interface and the interface with actual touch movement. The experimental results showed that the PS-type tactile interface exhibited almost the same ability as the interface involving actual touch movement. We also found that the force-to-velocity scaling factor of the cursor movement had a significant influence on the roughness detection capability of the interface. In addition, to apply our method to devices having small screens, such as mobile phones, we tried to restrict the cursor velocity in proportion to the object size that appears on the screen. The experimental results showed that the PS-type tactile interface can represent almost the same roughness information as the original object size.