Product Top-down Design Based On Parametric Technology

Top-down design is design components or parts in the environment of assembly, it contributes to discovering the interference of components, modifying and adjusting it in time. It makes the correlation of designed components or parts more correct, and reduces the time of modification. Furthermore, through defining associated parameter of components, we can completely realize correlative parameter modification in the components.In this thesis, product's function modeling and assembly model which supports Top-down design are researched. On the basis of parameterization technology based on feature and assembly modeling technology based on Top Basic Skelton, a Top-down modeling method which combines skeleton model with dominant parts is put forward, and accomplished a product design with it.Parameterization modeling technology makes data transfer instantaneous and exclusive in different layers. In this thesis, the main characteristic of parameter modeling technology and the parameter modeling method are analyzed, the parameterization modeling method based on feature which adapt Top-down design is researched.Conceptual design is a very important stage in process of design, the result of it usually is expressed with the product function structure chart. In the light of the idea of Top-down design, product's function structure is described with the theory of product function structure tree. Based on it, the function model is researched, which supports the method of Top-down design, and the expression of function model based on binary-tree was also put forward.Assembly model supports product design from conceptual design to components design, it completely and correctly transfer different models' design parameters, assembly layers and assembly information. The information structure of assembly model is researched,which includes the description method of assembly model, the assembly relations and it's expression. According to characteristic of Top-down design, the assembly model which support Top-down design and it's maintenance in the process of assembly modeling is studied.In the end, the modeling technology on Top Basic Skeleton assembly model is discussed. The expression of assembly information of product on TBS modeling was analyzed in details. Based on the theory of TBS, the Top-down modeling method which combines skeleton model with dominant parts was put forward, and completed the product's Top-down design with the Top-down modeling method.