A broadband tactile array on the fingertip

Abstract

A stimulator array is described which can deliver a wide range of displacement waveforms from each contactor, allowing vibratory stimuli to be targeted towards different populations of mechanoreceptors in the skin. The array has a working bandwidth of 20-400 Hz and 100 moving contactors covering an area of 1 cm2 on the fingertip. The array was validated with two experiments on the perception of moving vibratory targets within a uniform background vibration. In the first experiment, with target and background at the same frequency, equivalent discrimination of target movement was obtained at higher values of target/background amplitude ratio for 40-Hz stimuli than for 320-Hz stimuli. In the second experiment, discrimination of target movement within a different-frequency background (320-Hz target and 40-Hz background, or vice versa) was found to be much easier than within a same-frequency background. These results suggest that tactile spatial acuity is better at 320 Hz than 40 Hz and that it is possible to target different receptor populations in the skin by using these frequencies. However, there are problems with this interpretation: on the basis of characterization of touch receptors in previous studies, spatial acuity is expected to be worse at 320 Hz than at 40 Hz.

Vibrotactile localization on the arm: Effects of place, space, and age

“…Although the difference in performance between their two frequencies was statistically significant in favor of the non-PC stimuli, the absolute difference, even when the two tested sites were 10 mm apart on the hypothenar of the palm, was only approximately 5%. Similarly, Summers and Chanter (2002) have been able to show that spatial acuity for moving stimuli presented at 320 Hz (in the PC range) on a dense vibrotactile array on the fingertip was actually somewhat better than it was when stimuli were presented at 40 Hz (a non-PC frequency).…”

A dense array stimulator to generate arbitrary spatio-temporal tactile stimuli

“…The array can deliver vibratory frequencies between 20 and 400 Hz. The maximum displacement was reported to be 50 μm peak-to-peak at 40 Hz and 6 μm at 320 Hz (Summers and Chanter, 2002).…”

Haptic Edge Sharpness Perception with a Contact Location Display

“…Fingertip displays include pin-array devices (e.g., [18]), actuated plates that convey surface orientation and curvature by changing the orientation of a moving plate (e.g., [19], [20]), contact area display (e.g., [21]), slip display (e.g., [17]), contact location display (e.g., [1], [22]), skin stretch displays (e.g., [23], [24], [25]), thermal displays (e.g., [26]), and variable-friction surfaces modulated mechanically (e.g., [27]) or electrically (e.g., [28]). The present study uses the contact location display (see Fig.…”