Automatic Modeling And Virtual Assembly System For Parallel Mechanisms

Parallel mechanisms play an important role in industry. In the aspect of parallel mechanism design, structural synthesis and dimensional synthesis attracted much attention. In order to meet the increasing requirements in industry and research of parallel mechanism design, it's imperative to develop digital environment applicable to parallel mechanism design. Therefore, based on virtual prototyping technology and software engineering technology, a system supporting automatic modeling and virtual assembly for parallel mechanisms is developed.Modular components of parallel mechanisms, design variables and structure representations of modules are discussed. Depending on design variables mentioned above, Design For Assembly method and parametric modeling technology with functional features are applied to support create 3D primitive libraries of modules with integrated assembly feature information.By analyzing methods of CAD secondary development, the approach of Dynamic Link Library and API functions are adopted to develop the presented system, which integrated into UGII. In the automatic modeling procedure, parametric modeling and configuration design by modifying variable expressions is implemented. In UG assembly environment, part occurrence ID distribution principle for parts is proposed. Parts, and geometrical elements and valid assembly information in assembled parts can be recognized automatically. The assembly sequence according to the property of parallel mechanisms and assembly relations which depend on different assembly information are identified. Based on parametric primitive libraries, the function of sequential automatic assembly is implemented.Combined VC++6.0 with UG/Open API functions, UG/Open UIStyler, UG/Open MenuScript ect., the automatic modeling and virtual assembly systemfor parallel mechanisms integrated into UG NX2.0 is developed.