Perceived distance from hitting with a stick is altered by overlapping vibration to holding hand

Distance perception by hitting with a holding stick is quite important for the people with visual impairments who daily use white cane. If the mechanism of this perception is well understood, it can be applied for the development of more intuitive and simple electric white cane consisting of a range sensor and a haptic display. A hypothetical mechanical model of a stick and a holding palm told us that hitting at a closer point should induce a stronger vibration at thumb side of the palm, and percussing a farther point should induce equally distributed vibrations in the palm. To verify if this vibration distribution plays role in the distance perception, we conducted an experiment that superimpose vibration to the real vibration while percussing, to change the center of gravity of vibration. The experimental results showed that adding vibration to the thumb side shortened the perceived collision distance than adding vibration to the little-finger side, which partly agrees with our hypothetical model.