A behavioral layer architecture for telecollaborative virtual manufacturing operations

Abstract

The review of the existing systems for performing manufacturing tasks in a collaborative virtual environment highlights the limitations for modeling object behavioral characteristics. It is difficult for users to describe the tasks to be performed in the environment. A behavioral layer architecture is presented here to address these limitations. The layer consists of a virtual manufacturing lattice (VML) structure, an object library, and a virtual manufacturing script (VMS). The VML is a hierarchical structure to encapsulate object behavioral characteristics, which augments the scenegraph structure. The encapsulation is achieved by using a four-tuple structure hC; R; T ; Ei, where C is the composition structure of the node which contains geometry, material, texture, and location data, R is the precedence relationship element, T is the trajectory relationship element, and E is the event control list used to describe the state information about the object. The VMS is implemented as a script and a parser that serves as an interface between the user and collaborative virtual reality software. The script is a grammar-like structure to describe manufacturing tasks. In the behavioral layer architecture, the script is parsed, and calls are issued to the underlying functions to initiate the tasks and to manipulate the lattice structure to perform the specified tasks. Availability of network bandwidth is a key ingredient for using our system for telecollaboration. As part of an example to demonstrate the implementation of VML-VMS, a study of network latency and saturation is performed for different network medium, packet sizes, sampling rate, and network protocols to explore ways of reducing network latency and display frame jitter.Index Terms-Collaborative virtual environment, object behavior modeling, virtual manufacturing.

Simplified animation circuit for metadata-based behavior model query and retrieval

“…Millar et al in [3] gives a detailed review about the behaviour animation techniques, i.e., techniques to model the animated characters that could interact autonomously in the virtual environment. Banerjee et al [1] point out several limitations of scene graph structure in specifying object behaviours for virtual manufacturing operations and augment the scene graph structure by encapsulating object behavioural characteristics at node level to create a new tree structure called virtual manufacturing lattice (VML). Hendricks et al [2] point out two main problems with behaviour modelling: difficult to Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page.…”

Human knowledge acquisition from 3D interaction in virtual environments

“…Algorithms for different systems are very difficult to be integrated because their data are highly self-contained. Banerjee [28] mentioned a big limitation of object behavior description, and tried to give a structure to solve the problem.…”

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