Effect of fingertip skin stretch on perceived friction magnitude
Rendering friction in virtual haptic simulations is quite straightforward. This is typically done using a force feedback device, such as a Phantom, to haptically render friction forces. However, this experience lacks the cutaneous sensation of fingertip skin stretch that is experienced when touching real objects with our own hands. Portraying such skin stretch would result in a more realistic interaction experience. Furthermore, we hypothesized that the addition of skin stretch to friction that is rendered via force feedback alone may also alter the perceived magnitude of the rendered friction. Our experiments found this to be true.
The contact location display interfaces with a force feedback device, such as a Phantom through a contact element. The force feedback device applies forces to the user directly through through this contact element. In the case of these experiments, a rubber coated wood block was used as the contact element. Push-pull cables couple the motion of the linear actuator that is on the wrist of the user to the motion of the contact block that moves along the length of the user’s finger. The construction of the device is shown in the images below.
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Friction was rendered via force feedback driven by a modified Karnopp friction model, and the friction forces were used to impose skin stretch. The rendered skin stretch was based on the stretch in a virtual spring due to applied friction forces as depicted below.
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Our results showed the skin stretch as small as a quarter of a millimeter led to a perceived increase in friction magnitude. See the publications below for detailed findings.
Related Publications
- Sylvester, Nicholas D. and Provancher, William R., “Effects of Longitudinal Skin Stretch on the Perception of Friction,” In Proc. of the 2nd Annual World Haptics Conference, Tsukuba, Japan, March 22–24, 2007, p. 373–378.
- Provancher, William R. and Sylvester, Nicholas D., “Effects of Longitudinal Skin Stretch on the Perception of Friction,” Submitted to IEEE Transactions on Haptics, Aug. 2008, pp. 11. (In Review)
