Research On Spatial Layout Of Complex Mechanical Systems With Constraints And Its Industrial Aesthetic Design

The product's fast and automatic creative design lays the basis for the enterprise to complete with others in the worldwide market. So our research group presented a fast creative design theory system which is based on 3D design platform. Among this design theory system the modules such as automatic generation of symbol schemes, automatic identification of symbol scheme and library of various basic mechanisms have been finished in the early stage. Based on the above works, this dissertation mainly studied on the other modules of the design theory system such as automatic spatial layout of complex mechanical systems with constraints, automatic virtual assembly, and product's aesthetic design. The main works are given as follows:(1) The layout expression method including connecting relation and space position of basic mechanisms is given for complex mechanical system. Firstly, the connecting relation of basic mechanisms composing mechanical system is analyzed, and the layout models for three types connecting relations are built. In order to facilitate the space expression of basic mechanism, block-based layout model is built according to different cases of basic mechanism's input and output shaft. Secondly, based on the block-based layout model, the layout space determination method for different basic mechanism such as gear mechanism, cam basic mechanism, link mechanism and groove mechanism are given, and the automatic generation of layout parameters is realized by programming.(2) The automatic spatial layout optimization algorithm for complex mechanical system matching with the identification result of symbol scheme is presented. The math model for layout optimization is built firstly. Then using self-adaptive genetic algorithm, considering the interference status, connecting relation, direction constraint and angle constraint, the fitness function is constructed. By coding each mechanism with four integer number in given scope, the complex mechanism system is denoted with genetic code. By generating the legal population, selection, crossover and mutation with given generations, the layout optimization result of complex mechanism system is obtained at last.(3) Using object oriented method and secondary development environment of 3D platform, the automatic virtual assembly for the mechanical system matching with the symbol scheme is realized. The transform matrix of each basic mechanism stored in the stage of spatial layout is acquired firstly. Then according to the difference between basic mechanism's layout coordinate system and its modeling coordinate system, the above transform matrix need to be revised to make these two coordinate system same. At last, adopting the predefined assembly technology, every basic mechanism will be positioned at specific location by using the transform matrix data, and 3D automatic virtual assembly matching with symbol scheme is realized.(4) A kind of parametric-based industrial aesthetic design of product is presented in this dissertation. The appearance of product mainly depends on some key aesthetic factors, such as dimensions, ratios and so on. These factors can be taken as control parameters to model the appearance of product. In this dissertation, taking the industrial sewing machine as an example, based on UG platform and secondary development technology (UG/OPEN API), the aesthetic design of industrial sewing machine is realized. The results of the example demonstrate the validity of the proposed method.(5) An automatic spatial layout algorithm for complex mechanical systems with container constraint is proposed in this dissertation. The layout container is classified into two categories: convex and concave. Self-adaptive genetic algorithm is adopted to optimize mechanical systems with container constraint. In this algorithm, each basic mechanism is denoted with four integer genetic code. Human and machine interaction technique is adopted to control the location and orientation of the first basic mechanism. Two kinds of interference test methods are presented for different type of layout container. At last, based on the layout optimization results, adopting predefined assembly technique, automatic virtual assembly for the mechanical system within the layout container is realized.The innovations and distinctions of this dissertation are given as follows:(1) Automatic spatial layout design of complex mechanical systems with constraints is applied into product's fast creative design theory system, which makes mechanical system not only satisfy the industrial aesthetic design but also satisfy the requirement of long life and high reliability.(2) As an important module of fast creative design theory system, the 3D automatic virtual assembly matching with symbol schemes is realized, which make it possible to select the best creative design scheme from many design schemes by intuitionistic way.(3) A Parametric-based industrial aesthetic design method is presented. This method correlates product's aesthetic form factors and the key feature parameters of product model. By changing the key feature parameter, different style of product appearance will be generated.