Research And Application On The Visualization Technology Of Virtual Assembly For EMU Bogies

The Virtual Assembly System of EMU Bogie is developed specially to solve the problems in actual assembly and maintenance, such as not intuitive expression of assembly, un-shared information, high cost and long time for maintenance training. The Virtual Assembly System of EMU Bogie provides not only an analysis and research platform for designers and Technologists but also a training method for manufacturing, repair and maintenance personnel so as to improve the efficiency of the process design and maintenance.The thesis is intended the research on the simulating fluency of assembly process, the intuitionistic expression for complex assembly relations and 3D stereoscopic display of visualization in the Virtual Assembly System.The virtual assembly system basically requires the real-time responding for graphics regenerating and rendering and interactive operation, while PC computers provide only limited capacities. The Graphics acceleration is needed especially for the complex products such as EMU bogies. The LOD technique based on AABB bounding box is studied and implementated to simplify complex models in different details without affecting the visual effects of visualization. And the efficiency of the system is improved by calling different models in different scenes meanwhile visual effects are still acceptable.Because assembled parts cover and block each other, assembly relations can't be observed clearly. By building slicing planes in the virtual assembly system based on the slicing technology, the internal structure of the assembly can be expressed visually, and consequently the inductivity of the system is improved.Stereoscopic 3D display makes deep hierarchic stereoscopic visualization possible. It also makes users feel as if they were in there. By comparing and analyzing methods of perspective projection rotation, parallel projection and two-center projection, the two-center projection method is adopted and implemented to realize the 3D stereoscopic display due to its advantage of two-center projection in the virtual assembly system for EMU bogies.In the end, the virtual assembly process of EMU Bogie is visualized in the system and wheel sets and air spring assembly are used as cases to display the visualization support for the system. Finally the paper gives the conclusions and future research prospecting.