Assembly process modeling for virtual assembly process planning

Virtual assembly process planning (VAPP) provides a more efficient, intuitive and convenient method for assembly process planning. Previous efforts in this field are concentrated on how to assemble components together and how to analyze this assembly process in a virtual environment. However, how the interactive planning process can be modeled and organized, which is important for VAPP because of its significant influence on data organization and planning efficiency, are mostly not included. Based on analysis of the requirement of VAPP, a hierarchical assembly task list (HATL) model is proposed. In the model, assembly tasks are defined to express component assembling operations and are sequentially and hierarchically organized according to different subassemblies, which can perfectly model the construction process of product. For each assembly task, its major mission is to establish assembly relations, which is realized by an automatic geometrical constraint recognition mechanism. A three-layer virtual part model and a modified collision detection algorithm are firstly put forward to provide basic information for it. Then the automatic constraint recognition algorithm based on assembly intents filtering mechanism including destination intent, design intent and precedence intent, is detailed. All models and algorithms have been verified by a desktop-mode experiment VAPP system. However, it can also be suitable for immersive mode.