Miguel A. Otaduy: Research

Haptic Rendering

Haptic rendering is the computational technology that allows us to interact with virtual worlds through the sense of touch. It relies on an algorithm that simulates a virtual world in a physically-based manner and computes interaction forces, and a robotic device that transmits those interaction forces to the user. Haptics science is a multidisciplinary field that brings together psycophysics research for the understanding of tactile cues and human perception, mechanical engineering for the design of robotic devices, control theory for the analysis of the coupling between the real and virtual worlds, and computer science, in particular computer graphics, for the simulation of the virtual world and the design of the haptic rendering algorithm.

Six-degree-of-freedom (6-DoF) haptic rendering is the problem of computing the haptic interaction (force and torque) between a rigid tool manipulated by the user and other rigid objects in the virtual environment. In order to display stiff contact in a stable manner, feedback forces have to be updated at very high rates (e.g., 1 kHz). Therefore, 6-DoF haptic rendering of geometrically complex models requires efficient solutions to collision detection. One such solution relies on convex decomposition of the objects and the computation of penalty forces based on localized penetration depth [→].

Efficient methods for 6-DoF haptic rendering also include the extension of classical methods in graphical rendering. Levels of detail can be extended to the problem of collision detection to provide sensation-preserving haptic rendering [→], while haptic textures can be used for obtaining fast approximate contact forces between objects with rough surfaces [→]. The overall quality of a haptic rendering algorithm can be measured in terms of its stability and transparency, which can be enhanced using multirate algorithms that compute full contact handling at a moderately slow rate and evaluate feedback forces using a simplified model at a fast rate [→].

The addition of deformable objects to the virtual world increases the complexity of haptic rendering. Multirate methods can be extended to the case where a rigid tool manipulated by the user is in contact with a deformable environment [→], and also to the case where the tool itself is deformable. The solution employs robust models for contact handling on a slow rate, and the computation of a linearized contact model that is evaluated on a fast rate [→].

Students: Carlos Garre [→].

Collaborators: Ming Lin (UNC) [→], Young Kim (EWHA) [→].

Last modified June 10, 2009