Reseach On Enabling Technologies Of Distributed Collaborative Virtual Assembly System For Complex Product

When designing process of complex product is concerned, different design departments or supplier located in different area are usually involved, and it is very important to discover the potential mismatch in assembly as soon as possible in design process. The traditional assemble ability evaluation method must be based on the physical prototypes and designers have to take trial and error assembly for many times. A great deal of physical prototypes and trial assemblies will make the cost of design higher and the design period longer. The application of virtual reality in assembly design evaluation simulation can reduce the cost of design and design time and consequently make the product more competitive. On other hand, distributed virtual assembly provides a share virtual environment in which distributed design department or supplier can carry out collaborative virtual assembly evaluation through internet, thus it saves the cost of final product assembly evaluation time. Moreover, it is not need to produce and transport the physical prototypes. The digital model of products can be managed by the currently mature PDM system, thus it can guarantee the safety and security of design models better.Firstly, carefully studying on the state-of-art research situation and functional requirements of distributed collaborative virtual assembly and real-time rendering for complex virtual scene, the system architecture and hardware structure of the distributed virtual assembly system have been put forward, the enabling technologies have been figured out, including the multi-user collaborative assembly operation method, and cluster based parallel rendering and multi-channel stereoscopic display techniques.Secondly, the collaborative virtual assembly operation method based on HLA for multiple users is studied in distributed environment.. Those key points related with the construction of virtual assembly federation, the creation of federation object models, real-time join and quit of each user, virtual scene management, collaborative assembly operation and operation conflicts in distributed virtual assembly environment have been solved.Thirdly, mass data real-time rendering problem of complex product and multi-channel stereo display of virtual reality system are analyzed. A parallel rendering method based on dynamic view-frustum partitioning and sort-first architecture is proposed. The algorithms for load balancing and model partitioning have been put forward to increase rendering performance. The large scale scene real-time rendering and multi-channel stereo display problem are solved with this parallel rendering method.Finally, a distributed and collaborative virtual assembly system, which is based on the already existing IVAE system, is developed with the methods and techniques studied and mentioned above. The validity of this collaborative virtual assembly system had been proved by an example of multi-user collaborative automobile assembly.