Contact Location Display for Haptic Perception of Curvature and Object Motion

Abstract

We present a new tactile display for use in dexterous telemanipulation and virtual reality. Our system renders the location of the contact centroid moving on the user's fingertip. Constructed in a thimble-sized package and mounted on a haptic force-feedback device, it provides the user with concurrent feedback of contact location and interaction forces. We believe such a design will enable more versatile object manipulation and richer haptic interactions. To evaluate this display concept, we conducted two perceptual experiments. First, human subjects judged object curvature using both direct manipulation of physical models and virtual manipulation via the device. Results show similar levels of discrimination in real and virtual interactions, indicating the device can effectively portray contact information. Secondly, we investigated virtual interactions with rolling and anchored objects and demonstrated that users are able to distinguish the interaction type using our device. These experiments give insight into the sensitivity of human perception and suggest that even a simple display of the contact centroid location may significantly enhance telerobotic or virtual grasping tasks.

Haptic Perception of Real and Virtual Curvature

“…We can thus conclude that Morpheotron-type devices simulate curvature within the range of human haptic discrimination thresholds, i.e., virtual shapes are perceptually similar to real shapes. Our finding is in line with Provancher et al [8] who investigated curvature discrimination with four nonzero reference curves (between 25 and 100 m −1 ) for real and virtual stimuli. When using haptic devices, one should be aware that unwanted cues such as vibrations, control instabilities, stick-slip, mechanical artifacts, or even auditory signals can be informative to the participants.…”

Transfer of the curvature aftereffect in dynamic touch

“…Several other studies have investigated curvature perception by dynamic touch, but the curvature of the stimuli that were used varied from 19 to 120 m −1 , which is above the threshold for static touch with a single finger (Bodegård, Geyer, Grefkes, Zilles, & Roland, 2001;Bodegård et al, 2000;Provancher, Cutkosky, Kuchenbecker, & Niemeyer, 2005;Van der Horst & Kappers, 2007;. In such cases, dynamic contact was not required to perceive the shape of the stimulus, but it might have improved the accuracy.…”

Force and contact location shading thresholds for smoothly rendering polygonal models

“…As a relatively sophisticated adaptation of the work by Dostmohamed and Hayward, Frisoli et al present a miniaturized finger-based tilting plate tactile display that can be attached to a kinesthetic display [6]. Finally, the author's prior studies have shown the potential of contact location feedback for enhancing object curvature and motion cues [15].…”

“…The device's PID controller was run at 1 kHz and was programmed in C++ and executed under Windows XP using Windows multimedia timers. Further details about the design and control of this device may be found in [15]. …”

“…Our presented shading algorithm can also be used to provide force shading as an alternative to Morganbesser and Srinivasan's algorithm. This work builds on several recent studies to provide combined tactile and kinesthetic feedback [6,7] including ones using contact location tactile feedback in combination with a Phantom force feedback device [15,12]. While prior studies using contact location feedback were successful in showing the potential of this type of tactile feedback, these studies were conducted using highly specialized virtual environments composed of a collection of constant curvature segments [12].…”