Electrovibration: Influence of the applied force on tactile perception thresholds

We present a study on the influence of the applied force on tactile perception thresholds, during exploration of tactile textures generated with electrovibration. Combined with screen-integrated force detection this could lead to more realistic texture feedback on touch screens while exploring a virtual surface. From a first user study, three force levels corresponding to the light (0.2 N-1.5 N), medium (1.5 N-3.0 N), and high force (3.0 N-7.0 N) categories were deduced. In a second study, the users were asked to apply these force levels while following a line on the screen. We determined the perception thresholds of 10 participants for specific electrovibration stimuli (100 Hz, 160 Hz, 240 Hz, 360 Hz, and 540 Hz sine signals) using a staircase method. No force effect on the perception threshold has been measured for 100 Hz and 160 Hz, while it decreased with increasing applied force at 240 Hz, 360 Hz, and 540 Hz.