  A continuous stroking sensation on the skin can convey messages or emotion
cues. We seek to induce this sensation using a combination of illusory motion
and lateral stroking via a haptic device. Our system provides discrete lateral
skin-slip on the forearm with rotating tactors, which independently provide
lateral skin-slip in a timed sequence. We vary the sensation by changing the
angular velocity and delay between adjacent tactors, such that the apparent
speed of the perceived stroke ranges from 2.5 to 48.2 cm/s. We investigated
which actuation parameters create the most pleasant and continuous sensations
through a user study with 16 participants. On average, the sensations were
rated by participants as both continuous and pleasant. The most continuous and
pleasant sensations were created by apparent speeds of 7.7 and 5.1 cm/s,
respectively. We also investigated the effect of spacing between contact points
on the pleasantness and continuity of the stroking sensation, and found that
the users experience a pleasant and continuous linear sensation even when the
space between contact points is relatively large (40 mm). Understanding how
sequential discrete lateral skin-slip creates continuous linear sensations can
influence the design and control of future wearable haptic devices.
