Tactile Haptic Slip Display


Humans are able to manipulate fragile objects like eggs without dropping or crushing them, but this is challenging for robots. One reason is that human fingers are equipped with sensors that provide information on "incipient slip" the condition when the edges of our fingerprints begin to release from the object. Incipient slip is a cue that the object is being held with just enough force to keep it from falling from the grasp.

It is possible to build synthetic skins for robot fingers so that a computer can control forces using incipient slip. However prior to our development of a slip display, there had been no way to display remotely sensed slip to a human using a teleoperated robot system.

     
(Left) Slip display in use (Right) Exploded CAD drawing of the slip dislpay.      


The slip display is designed to be a modular attachment to a force feedback haptic device such as the PHANTOM from Sensable Technologies, Inc. The slip display is essentially an actuated sphere that can be spun in two dimensions. Using this combined system, we are able to simulate not only the shape of a virtual or remote environment, but also the 2-DOF sensation incipient or continuous sliding contact.

We have conducted several perceptual experiments to determine the limits of human slip perception under a variety of condidtions. We have also demonstrated that our device enables users of a teleoperated system to accomplish a task while applying less force than is possible without tactile slip feedback.

Videos:

  1. Slip Display Ball Motion 

  2. Display Attached to PHANTOM

Journal Publications:
  1. R. J. Webster III, T. E. Murphy, L. N. Verner, and A. M. Okamura. A Novel Two-Dimensional Tactile Slip Display: Design, Kinematics, and Perceptual Experiments.  ACM Transactions on Applied Perception, 2(2), 2005. 

Conference Publications:

  1. T. E. Murphy, R. J. Webster III, and A. M. Okamura, Design and Performance of a Two-Dimensional Tactile Slip Display. Eurohaptics, 130-137, 2004.