Interaction of Heterogeneous Haptic Devices Over the WWW 
Integrated Media Systems Center Annual Conference, Los Angeles, CA 2001

?	Authors: Professors (alphabetical)
?	Joćo P. Hespanha (Department of Electrical Engineering, USC)
?	Margaret McLaughlin (Annenberg School of Communication, USC)
?	Gaurav S. Sukhatme (Department of Computer Science, USC)

?	Authors: Research Assistants (alphabetical)
?	Minoo Akbarian (User Interface and Human Behavior)
?	Rajiv Garg (Software Architecture, Robotics, and Artificial Intelligence)
?	Weirong Zhu (Data Communication and Storage)

?	Funding provided by: National Science Foundation (NSF)

Abstract
In this paper we present a distributed architecture for haptic collaboration over the internet. We explicitly address the issue of latency (communication delay), thus providing a foundation for a shared haptic experience among distributed users. With respect to stability, latency is a critical factor that governs whether two users can truly share a common haptic experience. We propose an algorithm where the nature of the interaction between two hosts is decided dynamically based on the measured network latency between them. Users on hosts that are near each other (low communication latency) are dynamically added to fast local group. If the communication latency is high users are allowed a slower form of interaction where they can touch and feel objects but cannot exert forces on them. Users within a fast local group experience true haptic collaboration since the system is able to resolve the interaction forces between them fast enough to meet stability criterion. We discuss these creations, maintenance and updates mechanisms of local group for fast interaction, as well as synchronization mechanism for hosts participating in slower interactions.