A behavioral layer architecture for telecollaborative virtual manufacturing operations

The review of the existing systems for performing manufacturing tasks in a collaborative virtual environment highlights the limitations for modeling o bject 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 vir tual manufacturing lattice (VML) structure, an object library, and a virtua l manufacturing script (VMS). The VML is a hierarchical structure to encaps ulate object behavioral characteristics, which augments the scenegraph stru cture. The encapsulation is achieved by using a four-tuple structure (C, R, T, E), where C is the composition structure of the node which contains geo metry, material, texture, and location data, R is the precedence relationsh ip element, T is the trajectory relationship element, and E is the event co ntrol 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 betwee n the user and collaborative virtual reality software. The script is a gram mar-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 in gredient for using our system for telecollaboration. As part of an example to demonstrate the implementation of VML-VMS, a study of network latency an d saturation is performed for different network medium, packet sizes, sampl ing rate, and network protocols to explore ways of reducing network latency and display frame jitter.