Virtual Coupling Schemes for Position Coherency in Networked Haptic Virtual Environments

Опубликовано 6 сентября 2016, 16:56

In networked haptic environments ΓÇö used in surgical simulation training, maintenance task training, force-feedback enabled network games, etc.ΓÇö multiple users remotely collaborate sharing the same virtual space. In these environments, maintaining position coherency between the copies of the virtual object is vital to achieve consistency in collaboration, especially in the presence of time delays between users. To this end, client-server architectures are widely used to maintain position coherency in networked haptic environments. However, this approach introduces round trip delays for each user and, in addition, the collaboration becomes dependent on the ability of the client to maintain communication with the server. On the other hand, in peer-to-peer architectures ΓÇö where the information from each user is multicasted to all the other users ΓÇö time delay is reduced in half compared to client-server based methods. Nevertheless, this is the most difficult method for maintaining position coherency. In this work we present three virtual coupling schemes introduced to maintain position coherency, two of which utilize a peer-to-peer architecture and the remaining one, a client-server method. Their performances were compared for both constant and time-varying delays using the Internet, with experimental results that demonstrate that one of the virtual coupling schemes has a comparable performance to the server-based method. From this work we prove that peer-to-peer architectures are particularly useful in applications that use networked haptic environments.